Question

4x^2+19x=-21

Answer 1

4x^2 + 19x + 21
4(x^2 + 19x/4) + 21
4(x + 19/8)^2 - 19^2/16 + 21
(x+ 19/8)^2 - 19^2/(4*16) + 21/4, dividing out 4
(x+ 19/8)^2-25/64
( x+19/8 + 5/8)(x + 19/8 - 5/8)
(x + 24/8)(x + 14/8)
(x + 3)(x+ 7/4)
bringing back the 4 factor
4(x + 3)(x + 7/4)

Ans. 4(x + 3)(x + 7/4)