Question

$3x2 - 2x2 = 40 + 9$
$3x2 - 4 = 60 + 2x2$
$x2 - x - 20 = 0$

Answer 1

3x^2 - 2x^2 = 40 + 9
x^2 = 49
x = √49 = 7

3x^2 - 4 = 60 + 2x^2
3x^3 - 2x^2 = 60 + 4
x^2 = 64
x = √64 = 8

x^2 - x - 20 = 0
(+1 +- √1-4×-20)÷2
(1 +- √81)÷2
(1 +- 9)÷2
x' = (1+9)÷2 = 10÷2 = 5
x" = (1-9)÷2 = -8÷2 = -4