Question

Приведите к знаменателю 6/b-4 к знаменателю 1)5b-20 2)12-3b3)b в квадрате -4b4)b в квадрате -16

Answer 1

1)

$tt dfrac{6}{b-4} ^{(5} =dfrac{5cdot 6}{5cdot (b-4)} =dfrac{30}{5b-20}$

2)

$tt dfrac{6}{b-4} ^{(, (-3)} =dfrac{-3cdot 6}{-3cdot (b-4)} =dfrac{-18}{12-3b}$

3)

$tt dfrac{6}{b-4} ^{(b} =dfrac{bcdot 6}{bcdot (b-4)} =dfrac{6b}{b^2-4b}$

4)

$tt dfrac{6}{b-4} ^{(, (b+4)} =dfrac{(b+4)cdot 6}{(b+4)cdot (b-4)} =\ \ =dfrac{6b+24}{b^2-4^2} =dfrac{6b+24}{b^2-16}$

Answer 2

$displaystyle 1).;;;frac{6}{b-4} = frac{5*6}{5(b-4)} =frac{30}{5b-20}\\\ 2).;;; frac{6}{b-4} =-frac{6}{(4-b)} = -frac{3*6}{3*(4-b)} = -frac{18}{12-3b}\\\3).;;; frac{6}{b-4} =frac{6b}{(b-4)b} =frac{6b}{b^2-4b} \\\4).;;; frac{6}{b-4} = frac{6(b+4)}{(b-4)(b+4)} = frac{6b+24}{b^2-16}$