SOLUTION: 2r^2+10r+11=0

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Question 266123: 2r^2+10r+11=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

2r%5E2%2B10r%2B11=0 Start with the given equation.


Notice that the quadratic 2r%5E2%2B10r%2B11 is in the form of Ar%5E2%2BBr%2BC where A=2, B=10, and C=11


Let's use the quadratic formula to solve for "r":


r+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


r+=+%28-%2810%29+%2B-+sqrt%28+%2810%29%5E2-4%282%29%2811%29+%29%29%2F%282%282%29%29 Plug in A=2, B=10, and C=11


r+=+%28-10+%2B-+sqrt%28+100-4%282%29%2811%29+%29%29%2F%282%282%29%29 Square 10 to get 100.


r+=+%28-10+%2B-+sqrt%28+100-88+%29%29%2F%282%282%29%29 Multiply 4%282%29%2811%29 to get 88


r+=+%28-10+%2B-+sqrt%28+12+%29%29%2F%282%282%29%29 Subtract 88 from 100 to get 12


r+=+%28-10+%2B-+sqrt%28+12+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


r+=+%28-10+%2B-+2%2Asqrt%283%29%29%2F%284%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


r+=+%28-10%2B2%2Asqrt%283%29%29%2F%284%29 or r+=+%28-10-2%2Asqrt%283%29%29%2F%284%29 Break up the expression.


So the solutions are r+=+%28-10%2B2%2Asqrt%283%29%29%2F%284%29 or r+=+%28-10-2%2Asqrt%283%29%29%2F%284%29