Ericka A. answered • 04/28/21
Experienced and Certified Tutor
You can solve this problem one of two ways (quadratic formula or box method). First, you have to set (X) and (X-7) equal to 60. The equation should look like (x)(x-7)=60. Then you would distribute the x into (x-7) or in other words multiple the two which would be x2 -7x=60. Next, set the equation equal to zero by moving the 60 over the equal sign. When you move a number over the equal sign the sign changes too. So your new equation would be x2-7x-60=0. Now it's time to solve for X. With the box method you would draw a box and section it into fours. On the top left section you would write x2. On the bottom right section you would write -60. Then your two empty boxes have to equal -7x. Then work backwards, try to find two factors that equal to -60. These factors when added together should also equal -7. For instance -4*15=60, but when you add -4+15 it equals 11. So our factors can't be -4 and 15. But 12*-5=60 and 12+-5=-7, so these are our factors. When you fill out the rest of your box you should end with (x+12) and (x-5). Then it's time to solve for X. Set both factors equal to 0. It will be x+12=0 and x-5=0. You need to get X by itself so move the number over the equal side (don't forget to change the sign.) The answer is x=-12 and x=5.
You could also use the quadratic formula. You would use the same equation, x2-7x-60=0. A would be 1, B is -7, and C is -60. Plug the numbers into the formula and using a calculator solve for x.
