Question

4x^2+3x+5=0 by completing square method ​

Answer 1

Answer:

4x^2×3x=-5

Divide both the sides by 4

x^2+3/4x=-5/4 ............eqn 1.

Third term = [1/2 *coeficient of x]^2

=[1/2*3/4]^2

=1/4*9/16

=9/64

add 9/64 on both the sides of eqn 1.

x^2+3/4x+9/64 = -5/4 +9/64

(x+3/8)^2= -80+9/64

(x+3/8)^2 = -71/64

By taking square root on both the sides

x+3/8 = + , - (-√71)/8

x= -3/8 + (-√71)/8 OR x= -3/8 -(-√71)/8

x=-3/8-√71 /8 Or x=-3/8+√71/8

x= -3-√71/8 Or x-3+√71/8