Question

Find the mistake, fix it and solve.

2) f(x) = 2x² + 7x - 4
0 = 2x² + 7x - 4
0 = 2x² + 8x - x - 4
0 = (2x² + 8x) (- x - 4)
0 = 2x (x + 4) + 1(x + 4)
0 = (2x+1) (x+4)
x = -¹
x = -4

Answer 1

2x² + 7x - 4 = 0

2x² + 8x - x - 4 = 0

2x(x + 4) - 1(x + 4) = 0

(2x - 1)(x + 4) = 0

x = 1/2, -4