(5+4x)квадрат=(9-21х)(4х+5(

Question

(5+4x)квадрат=(9-21х)(4х+5(

Answer 1

(4x+5)^2-(9-21x)(4x+5)=0;
(4x+5)(4x+5-9+21x)=0;
(4x+5)(25x-4)=0;
4x+5=0 или 25x-4=0;
x = -1,25 или x = 0,16