Question

Solve
x² +10x - 15=0 by square method​

Answer 1

solution:-

=> x² +10x - 15=0

=> x² + 10x = 15

Take the coefficient of x , which is 10 , divide by two, giving 5 , and finally square it giving 25

so, by adding 25 both side, we get,

=> x² + 10x + 25 = 40

=> x² + 5x + 5x + 25 = 40

=> x ( x + 5 ) + 5 ( x + 5 ) = 40

=> ( x + 5 ) ( x + 5 ) = 40

=> ( x + 5 )² = 40

=> x + 5 = √40

=> x = √ 40 - 5

i.e.

=> x = - 5 ± √ 40

hence,

x = - 5 + √ 40 or - 5 - √ 40

i hope it helps you.