Question

-3x2 + 30x - 90 = 0.

Answer 1

Use the quadratic formula: \(\sf \large \frac{-b \pm \sqrt{b^2-4ac}}{2a}\) when you have: \(\sf \color{red}{ax^2+bx+c}\)

Answer 2

okay. thanks.

Answer 3

Simplify first by dividing throughout by -3
-3x^2 + 30x - 90 = 0
-3(x^2 - 10x + 30) = 0
x^2 - 10x + 30 = 0
use the quadratic formula.

Answer 4

okay, thank you..

Answer 5

you are welcome.

Answer 6

i did that, i seriously dont understand. i think its the third answer.

Answer 7

x^2 - 10x + 30 = 0
a = 1, b = -10, c = 30\[\frac{ -b \pm \sqrt{b ^{2} - 4ac} }{ 2a } = \frac{ -(-10) \pm \sqrt{(-10) ^{2} - 4(1)(30)} }{ 2(1) } = \frac{ 10 \pm \sqrt{100 - 120} }{ 2 }\]\[\frac{ 10 \pm \sqrt{-20} }{ 2 } = \frac{ 10 \pm \sqrt{-5 * 4} }{ 2 } = \frac{ 10 \pm 2 * i5 }{ 2 } = 5 \pm i5\]