Question

x square + x - 20 = 0​

Answer 1

Step-by-step explanation:

Hi ,

Given quadratic equation is

x² + x - 20 = 0

x² + x = 20

x² + 2 × x × 1/2 = 20

x² + 2 × x × 1/2 + ( 1/2 )² = 20 + ( 1/2 )²

( x + 1/2 )² = 20 + 1/4

( x + 1/2 )² = ( 80 + 1 )/4

( x + 1/2 )² = 81/4

x + 1/2 = ± √( 81/4 )

x + 1/2 = ± 9/2

x = -1/2 ± 9/2

x = ( -1/2 + 9/2 ) or x = ( -1/2 - 9/2 )

x = 8/2 or x = -10/2

x = 4 or x = -5

I hope this helps you.

: )

Answer 2

Answer:

${x}^{2} + x + - 20 = 0$

by middle term splitting,

${x}^{2} + 5x - 4x - 20 = 0$

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

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

if,

(x+5)=0

x=-5

if,

(x-4)=0

x=4