Solving quadratic equations?

Question

Could you tell me how to solve this one, and where I have put the question marks, explain how to get the correct signs (plus or minus). Thanks!

x^ - 7x - 30

(x ? 10) (x ? 3) ???

Answer 1

ok here's the best way,

in your equation, x^2 - 7x - 30, think of 2 numbers that multiply to negative 30 and add up to negative 7. That would be negative 10 and positive 3.

-10 x 3 = -30

-10 + 3 = -7

therefore the answer is (x -10) (x+3)

so the general rule is, look for 2 numbers that when multiplied together equal the last number in the equation and when added together equal the second number in the equation.  

Answer 2

(x -10)(x+3)

so answers are x=10 and x=-3

you got it!