SOLUTION: Solve by factoring: x2 – 9x = -20

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve by factoring: x2 – 9x = -20       Log On


   

Question 113714: Solve by factoring:
x2 – 9x = -20
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-9x+=-20 Start with the given equation


x%5E2-9x%2B20=0 Add 20 to both sides



%28x-5%29%28x-4%29=0 Factor the left side (note: if you need help with factoring, check out this solver)



Now set each factor equal to zero:

x-5=0 or x-4=0

x=5 or x=4 Now solve for x in each case


So our solutions are x=5 or x=4


Notice if we graph y=x%5E2-9x%2B20 we get

+graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C+x%5E2-9x%2B20%29+

and we can see that the graph has roots at x=5 and x=4, so this verifies our answer.