Question

4a^2+8a-20=0
By completing the square

Answer 1

4a² + 8a - 20 = 0
a = -8 +/- √(8² - 4(4)(-20))
2(4)
a = -8 +/- √(64 + 320)
8
a = -8 +/- √384
8
a = -8 +/- 19.59591794
8
a = -8 + 19.59591794 a = -8 - 19.59591794
8 8
a = 11.59591794 a = -27.59591794
8 8
a = 1.449489743 a = -3.443813782

Answer 2

I'm not sure but I think it is a=−1±6√
a≈1.44948974,−3.44948974