X^2-14x+40=0
how do i solve that

I have no idea how to explain it so you would understand it, but just know that you need to have factors of the third number (40(with no variables)) be equal to the second number (-14x(Which only has a variable (not squared)))
Therefore a factor would be -10 and -4, since -10*-4=40 and -10+(-4)= -14 
With these two numbers you can set it up so that it's like this;
(x-10)(x-4)
Having this, you now have 2 equations;
 x-10 = 0
and
x-4=0 (Don't ask why)
So now you solve for x, making it 10 or 4

It's like discovering the answer to a puzzle. the purpose in solving an equation is to find the value or values of the variable that makes it a true statement. any value of the variable that makes the equation true is called a solution to the equation.

Well is there a picture