Respuesta :

First combine like term

(-5x^3+2x^3) + x = 7- 3x^3

After add -5x^3 and +2x^3 together because it has like term is equal -3x^3

-3x^3 + x = 7-3x^3

Plus -3x^3 from both side

Left x alone you get

X= 7