Question

s²-4s-21=0 solving quadratic equation by completing th square

Answer 1

Answer:

S=7 or S=-3

Step-by-step explanation:

Given: s2-4s-21=0

Solved :

s2-(7-3)s-21=0

s2-7s+3s-21=0

s(s-7)+3(s-7)=0

Taking s-7 common:

(s-7)(s+3)=0

Hence :

Either

s-7=0

s=7

Or

s+3=0

s=-3

HOPE this helps you thankyou