Mathematics?

Question

x^2 + 3x = 28

I need to factor it so I can solve it via the quadratic equation
Can you explain how I would factor this?
thanks :)

Answer 1

x ² + 3 x - 28 = 0
(x + 7) (x - 4) = 0
x = - 7 , x = 4

Answer 2

First, get everything on one side of the equation. You do this by subtracting both sides of the equation by 28, leaving:

x^2 + 3x - 28 = 0.

Now, use the quadratic equation and plug in values for a, b, and c... a, b, and c represent the coefficient of each term; here: a = 1, b = 3, c = -28. So plug those values in the quadratic equation and solve. Keep in mind you should get 2 answers (due to the +/- that the root of the eqn carries).

You could have also done this:

x^2 + 3x - 28 = 0

Factored:

(x + 7)(x - 4) = 0

Knowing that (anything)*(zero) = zero, we can set each ()'s up individually equal to zero and solve:

x+7=0 -----> x = -7
x-4=0 ------> x = 4.

Therefore, you answers are x = 4, -7.

The quadratic equation should produce the same results.

NOTE: You can ALWAYS rely on the quadratic equation!

Answer 3

x^2+3x=28
or x^2+3x-28=0
or x^2-4x+7x-28=0
or x(x-4)+7(x-4)=0
or (x+7)(x-4)=0
either x+7=0 or x-4=0
or x=-7 or x=4 ,This is via factorisation,you can solve it via quadratic equation method also ,which is
x={-b+-sq rt(b^2-4ac)}/2a ,for the equation ax^2+bx+c=0 ans

Answer 4

quadratic formula solution requires your equation be set equal to zero...then follow the formula