Pertanyaan

lim x → 3 6 x − 9 − x 2 − 2 x + 6 3 x 2 − 11 − 3 x + 7 = ....

$lim_{x \to 3} \frac{3 x ^{2} - 11 - 3 x + 7}{6 x - 9 - x ^{2} - 2 x + 6} =$ ....

R. RGFLSATU

Master Teacher

Jawaban terverifikasi

Jawaban

jawaban yang tepat adalah D.

Pembahasan

Perhatikan bahwa jika dilakukan substitusi x = 3 , maka didapatkan hasil . Sehingga perlu dicari cara lain untuk mencari nilai limitnya. Perhatikan bahwa Jadi, jawaban yang tepat adalah D.

Perhatikan bahwa jika dilakukan substitusi x = 3, maka didapatkan hasil .
Sehingga perlu dicari cara lain untuk mencari nilai limitnya.

Perhatikan bahwa

$begin mathsize 14px style limit as straight x rightwards arrow 3 of fraction numerator square root of 3 straight x squared minus 11 end root minus square root of 3 straight x plus 7 end root over denominator square root of 6 straight x minus 9 end root minus square root of straight x squared minus 2 straight x plus 6 end root end fraction equals limit as straight x rightwards arrow 3 of open parentheses fraction numerator square root of 3 straight x squared minus 11 end root minus square root of 3 straight x plus 7 end root over denominator square root of 6 straight x minus 9 end root minus square root of straight x squared minus 2 straight x plus 6 end root end fraction times fraction numerator square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root over denominator square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root end fraction times fraction numerator square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root over denominator square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root end fraction close parentheses equals limit as straight x rightwards arrow 3 of fraction numerator open parentheses open parentheses 3 straight x squared minus 11 close parentheses minus open parentheses 3 straight x plus 7 close parentheses close parentheses open parentheses square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root close parentheses over denominator open parentheses open parentheses 6 straight x minus 9 close parentheses minus open parentheses straight x squared minus 2 straight x plus 6 close parentheses close parentheses open parentheses square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root close parentheses end fraction equals limit as straight x rightwards arrow 3 of fraction numerator open parentheses 3 straight x squared minus 11 minus 3 straight x minus 7 close parentheses open parentheses square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root close parentheses over denominator open parentheses 6 straight x minus 9 minus straight x squared plus 2 straight x minus 6 close parentheses open parentheses square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root close parentheses end fraction equals limit as straight x rightwards arrow 3 of fraction numerator open parentheses 3 straight x squared minus 3 straight x minus 18 close parentheses open parentheses square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root close parentheses over denominator open parentheses negative straight x squared plus 8 straight x minus 15 close parentheses open parentheses square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root close parentheses end fraction equals limit as straight x rightwards arrow 3 of fraction numerator 3 straight x squared minus 3 straight x minus 18 over denominator negative straight x squared plus 8 straight x minus 15 end fraction times limit as straight x rightwards arrow 3 of fraction numerator square root of 6 straight x minus 9 end root plus square root of straight x squared minus 2 straight x plus 6 end root over denominator square root of 3 straight x squared minus 11 end root plus square root of 3 straight x plus 7 end root end fraction equals limit as straight x rightwards arrow 3 of fraction numerator 3 open parentheses straight x squared minus straight x minus 6 close parentheses over denominator negative open parentheses straight x squared minus 8 straight x plus 15 close parentheses end fraction times fraction numerator square root of 6 open parentheses 3 close parentheses minus 9 end root plus square root of open parentheses 3 close parentheses squared minus 2 open parentheses 3 close parentheses plus 6 end root over denominator square root of 3 open parentheses 3 close parentheses squared minus 11 end root plus square root of 3 open parentheses 3 close parentheses plus 7 end root end fraction equals limit as straight x rightwards arrow 3 of fraction numerator 3 open parentheses straight x plus 2 close parentheses open parentheses straight x minus 3 close parentheses over denominator negative open parentheses straight x minus 3 close parentheses open parentheses straight x minus 5 close parentheses end fraction times fraction numerator square root of 9 plus square root of 9 over denominator square root of 16 plus square root of 16 end fraction equals limit as straight x rightwards arrow 3 of fraction numerator 3 open parentheses straight x plus 2 close parentheses over denominator negative open parentheses straight x minus 5 close parentheses end fraction times fraction numerator 3 plus 3 over denominator 4 plus 4 end fraction equals fraction numerator 3 open parentheses 3 plus 2 close parentheses over denominator negative open parentheses 3 minus 5 close parentheses end fraction times 6 over 8 equals fraction numerator 3 open parentheses 5 close parentheses over denominator negative open parentheses negative 2 close parentheses end fraction times 6 over 8 equals 15 over 2 times 6 over 8 equals 90 over 16 equals 45 over 8 end style$

Jadi, jawaban yang tepat adalah D.