Question

(3х+7)(3х-7)-3х(3х+1)=5

6х-1/4 - 3х+1/3=1/4 (/- дробь)

х(2-х)/2+х(3+2х)/4=1

(6х-1)(х+1)=20

Answer 1

Не знаю как делать 4

Answer 2

(6x-1)(x+1)=20

Answer 3

6x^2+6x-x-1=20
6x^2+5x=21
x(6x+5)=21
6x-5=21/x
6x=21-5x/x
6=21-5x
5x=15
x=3