SOLUTION: how do you solve this question? 2x^2 + 18x + 28 = 0

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Question 527063: how do you solve this question? 2x^2 + 18x + 28 = 0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

2x%5E2%2B18x%2B28=0 Start with the given equation.


Notice that the quadratic 2x%5E2%2B18x%2B28 is in the form of Ax%5E2%2BBx%2BC where A=2, B=18, and C=28


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-%2818%29+%2B-+sqrt%28+%2818%29%5E2-4%282%29%2828%29+%29%29%2F%282%282%29%29 Plug in A=2, B=18, and C=28


x+=+%28-18+%2B-+sqrt%28+324-4%282%29%2828%29+%29%29%2F%282%282%29%29 Square 18 to get 324.


x+=+%28-18+%2B-+sqrt%28+324-224+%29%29%2F%282%282%29%29 Multiply 4%282%29%2828%29 to get 224


x+=+%28-18+%2B-+sqrt%28+100+%29%29%2F%282%282%29%29 Subtract 224 from 324 to get 100


x+=+%28-18+%2B-+sqrt%28+100+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


x+=+%28-18+%2B-+10%29%2F%284%29 Take the square root of 100 to get 10.


x+=+%28-18+%2B+10%29%2F%284%29 or x+=+%28-18+-+10%29%2F%284%29 Break up the expression.


x+=+%28-8%29%2F%284%29 or x+=++%28-28%29%2F%284%29 Combine like terms.


x+=+-2 or x+=+-7 Simplify.


So the solutions are x+=+-2 or x+=+-7


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Jim