How do you write 3x(10-4x)-6(x=5)+15 in standard form?

Oct 24, 2017

$- 4 {x}^{2} + 8 x - 15 = 0$

Explanation:

$a {x}^{2} + b x + c = 9$is the standard form of quadratic equation.

Removing braces,

$30 x - 12 {x}^{2} - 6 x = 30 + 15$

$- 12 {x}^{2} + 24 x = 45$

$- 12 {x}^{2} + 24 x - 45 = 0$

# dividing both sides by 3,

$- 4 x 2 + 8 x - 15 = 0$