Tìm x, biết: x(x - 3) + 5x = x^2 - 8
Tìm x, biết: x(x − 3) + 5x = x2 – 8.
x(x − 3) + 5x = x2 – 8
x(x − 3) + 5x − x2 + 8 = 0
x2 − 3x + 5x − x2 + 8 =0
2x + 8 = 0
2x = −8
x = −4
Vậy x = −4.