SOLUTION: solve for x Subtract x from both sides.

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Question 299539: solve for x
Subtract x from both sides.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

3x%5E2-11x=20 Start with the given equation.


3x%5E2-11x-20=0 Subtract 20 from both sides.


Notice that the quadratic 3x%5E2-11x-20 is in the form of Ax%5E2%2BBx%2BC where A=3, B=-11, and C=-20


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-%28-11%29+%2B-+sqrt%28+%28-11%29%5E2-4%283%29%28-20%29+%29%29%2F%282%283%29%29 Plug in A=3, B=-11, and C=-20


x+=+%2811+%2B-+sqrt%28+%28-11%29%5E2-4%283%29%28-20%29+%29%29%2F%282%283%29%29 Negate -11 to get 11.


x+=+%2811+%2B-+sqrt%28+121-4%283%29%28-20%29+%29%29%2F%282%283%29%29 Square -11 to get 121.


x+=+%2811+%2B-+sqrt%28+121--240+%29%29%2F%282%283%29%29 Multiply 4%283%29%28-20%29 to get -240


x+=+%2811+%2B-+sqrt%28+121%2B240+%29%29%2F%282%283%29%29 Rewrite sqrt%28121--240%29 as sqrt%28121%2B240%29


x+=+%2811+%2B-+sqrt%28+361+%29%29%2F%282%283%29%29 Add 121 to 240 to get 361


x+=+%2811+%2B-+sqrt%28+361+%29%29%2F%286%29 Multiply 2 and 3 to get 6.


x+=+%2811+%2B-+19%29%2F%286%29 Take the square root of 361 to get 19.


x+=+%2811+%2B+19%29%2F%286%29 or x+=+%2811+-+19%29%2F%286%29 Break up the expression.


x+=+%2830%29%2F%286%29 or x+=++%28-8%29%2F%286%29 Combine like terms.


x+=+5 or x+=+-4%2F3 Simplify.


So the solutions are x+=+5 or x+=+-4%2F3