Question

-(4/7)*X Во второй +28=0

Answer 1

-(4/7)*x^2+28=0
-4/7*x^2+28=0
-4x^2/7+28=0
-4x^2/7+28/1=0
-4x^2/7+196/7
-4x^2+196
-2x^2+98
-x^2+49
-x=7