How do you solve #x^2 -5x= -7# using the quadratic formula?

Question

4923 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-05-16T03:10:46

Add #7# to both sides of the equation to make it equal to #0#:

#x^2 - 5x + 7 = 0#

Then use the quadratic formula and plug in the values:

#x = (-b +-sqrt(b^2-4ac))/(2a)#

#x = (5 +-sqrt(25-4(1)(7)))/(2(1)) = (5+-sqrt(-3))/2#

If you've learned about complex numbers, this can be simplified to

#x = 5/2 +- (isqrt(3))/2#