Answer:
Below in BOLD.
Step-by-step explanation:
5x^2 - 6x - 2 = 0
Quadratic formula for ax^2 + bx + c = 0 is
x = [-b ± √(b^2 - 4ac)]/ 2a
Here we have a = 5, b = -6 and c = -2
so x = [-(-6) ± √((-6)^2 - 4*5*-2)]/ 2*5
= [ 6 ± √(36 + 40)] / 10
= 0.6 ± √76 / 10
= 0.6 ± 0.8718
= 1.4718, -0.2718
= 1.5, -0.3 to one decimal place.
x^2 + 3x = 40
x^2 + 3x - 40 = 0
We can factor this one:
(x - 5)(x + 8) = 0
x - 5 = 0 giving x = 5 and
x + 8 = 0 giving x = -8.
Answer x = -8, 5.
