SOLUTION: Use the quadratic formula to solve: x^2+12x+11=0

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Use the quadratic formula to solve: x^2+12x+11=0      Log On


   

Question 178398This question is from textbook
: Use the quadratic formula to solve: x^2+12x+11=0 This question is from textbook

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2%2B12x%2B11=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=1, b=12, and c=11


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%2812%29+%2B-+sqrt%28+%2812%29%5E2-4%281%29%2811%29+%29%29%2F%282%281%29%29 Plug in a=1, b=12, and c=11


x+=+%28-12+%2B-+sqrt%28+144-4%281%29%2811%29+%29%29%2F%282%281%29%29 Square 12 to get 144.


x+=+%28-12+%2B-+sqrt%28+144-44+%29%29%2F%282%281%29%29 Multiply 4%281%29%2811%29 to get 44


x+=+%28-12+%2B-+sqrt%28+100+%29%29%2F%282%281%29%29 Subtract 44 from 144 to get 100


x+=+%28-12+%2B-+sqrt%28+100+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%28-12+%2B-+10%29%2F%282%29 Take the square root of 100 to get 10.


x+=+%28-12+%2B+10%29%2F%282%29 or x+=+%28-12+-+10%29%2F%282%29 Break up the expression.


x+=+%28-2%29%2F%282%29 or x+=++%28-22%29%2F%282%29 Combine like terms.


x+=+-1 or x+=+-11 Simplify.


So the answers are x+=+-1 or x+=+-11