Question

(x+7) (x+9) = (x+5) (x+21)​

Answer 1

HEYA!!

Answer:

-4.2

Step-by-step explanation:

(×+7)(×+9)=(×+5)(×+21)

${x}^{2} + 9x + 7x + 63 = {x}^{2} + 5x + 21x + 105$

${x}^{2} + 16x + 63 = {x}^{2} + 26x + 105$

${x}^{2} - {x}^{2} + 16x - 26x + 63 - 105 = 0$

$- 10x - 42 = 0$

$- 10x = 42 \\ x = - \frac{42}{10}$

$x = -4.2$

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