Question

Помогите пожайлуста.
Заранее спасибо.​

Answer 1

2.5(16+x²+8x)+7(25-x²)=295-4.5x²

40+2.5x²+20x+175-7x²=295-4.5x²

2.5x²+4.5x²-7x²+20x=295-40-175

20x=80

x=4

Answer 2

$\displaystyle \tt 2,5(4+x)^2+7(5-x)(5+x)=295-4,5x^2\\\displaystyle \tt 2,5(16+8x+x^2)+7(25-x^2)=295-4,5x^2\\\displaystyle \tt 40+20x+2,5x^2+175-7x^2=295-4,5x^2\\\displaystyle \tt 215+20x-4,5x^2=295-4,5x^2\\\displaystyle \tt 215+20x=295\\\displaystyle \tt 20x=295-215\\\displaystyle \tt 20x=80\\\displaystyle \tt x=80\div20\\\displaystyle \tt \bold{x=4}$