(4х+1)в квадрате -(1-3х)(1+3х)=(5х+2)в квадрате

(4x+1)^2 - (1-3x)(1+3x)=(5x+2)^2

(16x^2+8x+1) - (1 - 9x^2) = 25x^2+20x+4

16x^2+8x+1 - 1+9x^2 = 25x^2+20x+4

25x^2 + 8x = 25x^2+20x+4

25x^2 - 25x^2 - 20x + 8x = 4

-12x = 4

x = -4/12

x = -1/3

Ответ: -1/3

(4х+1)²-(1-3х)(1+3х)=(5х+2)²

16х²+8х+1-(1-9х²)=25х²+20х+4

16х²+8х+1-1+9х²=25х²+20х+4

25х²+8х-25х²-20х-4=0

-12х-4=0

-12х=4

х=-4/12

х=-1/3