SOLUTION: solve 7xsquared+4x-3=0

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Question 316795: solve 7xsquared+4x-3=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

7x%5E2%2B4x-3=0 Start with the given equation.


Notice that the quadratic 7x%5E2%2B4x-3 is in the form of Ax%5E2%2BBx%2BC where A=7, B=4, and C=-3


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-%284%29+%2B-+sqrt%28+%284%29%5E2-4%287%29%28-3%29+%29%29%2F%282%287%29%29 Plug in A=7, B=4, and C=-3


x+=+%28-4+%2B-+sqrt%28+16-4%287%29%28-3%29+%29%29%2F%282%287%29%29 Square 4 to get 16.


x+=+%28-4+%2B-+sqrt%28+16--84+%29%29%2F%282%287%29%29 Multiply 4%287%29%28-3%29 to get -84


x+=+%28-4+%2B-+sqrt%28+16%2B84+%29%29%2F%282%287%29%29 Rewrite sqrt%2816--84%29 as sqrt%2816%2B84%29


x+=+%28-4+%2B-+sqrt%28+100+%29%29%2F%282%287%29%29 Add 16 to 84 to get 100


x+=+%28-4+%2B-+sqrt%28+100+%29%29%2F%2814%29 Multiply 2 and 7 to get 14.


x+=+%28-4+%2B-+10%29%2F%2814%29 Take the square root of 100 to get 10.


x+=+%28-4+%2B+10%29%2F%2814%29 or x+=+%28-4+-+10%29%2F%2814%29 Break up the expression.


x+=+%286%29%2F%2814%29 or x+=++%28-14%29%2F%2814%29 Combine like terms.


x+=+3%2F7 or x+=+-1 Simplify.


So the solutions are x+=+3%2F7 or x+=+-1