Question

solve by completing square method-the sum given
$x {}^{2} +x - 20 = 0$

Answer 1

x² + x - 20

x² + 5x - 4x - 20 = 0

x (x +5) -4(x+5) = 0

(x - 4)(x+5 ) = 0

x - 4 = 0

x = 4

x + 5 = 0

x = -5