Question

11. Ifx + 7 is the mean proportional between (x +3
and (x + 12), find the value of x.​

Answer 1

Answer:

x=13

Step-by-step explanation:

Given:

(x+3):(x+7)=(x+7):(x+12)

Therefore,

(x+7)²=(x+3)(x+12)

x²+49+14x=x(x+12)+3(x+12)

x²+49+14x=x²+12x+3x+36

x²+49+14x=x²+15x+36

Divide both sides by x²

49+14x=15x+36

49-36=15x-14x

13=x

x=13