Question

can anyone solve 4x^2 + 12x - 40 ? you would have to find what multiplies to get -40 but adds to get 12, but you do something with th 4x^2 as well

Answer 1

There's really nothing to solve, since there's no equation there.
Perhaps you want that expression factored. We can do that.

First, all 3 terms share a common factor of 4. Let's pull that out,
and see what's left to be factored:

4x² + 12x - 40 = 4 (x² + 3x - 10) .

Now, the expression left inside the parentheses looks
like it might be a lot easier to handle.

Here's what the whole expression looks like after the
quadratic inside the parentheses is factored:

4 (x² + 3x - 10) = 4 (x + 5) (x - 2) .

There it is. Understand ... we haven't changed anything,
and we haven't solved anything. We only wrote the original
expression in a different form. It's still just an expression that
stands for a number, and we won't know the number until
somebody tells us the value of 'x' .