SOLUTION: Solve for x: 2x(sq)-4x=3 I have the answer down as 4+/-(sqrt 40) over 4 but i need to know the steps that led to there....plz hlp

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: Solve for x: 2x(sq)-4x=3 I have the answer down as 4+/-(sqrt 40) over 4 but i need to know the steps that led to there....plz hlp      Log On


   

Question 322828: Solve for x:
2x(sq)-4x=3
I have the answer down as 4+/-(sqrt 40) over 4 but i need to know the steps that led to there....plz hlp
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

2x%5E2-4x=3 Start with the given equation.


2x%5E2-4x-3=0 Subtract 3 from both sides.


Notice that the quadratic 2x%5E2-4x-3 is in the form of Ax%5E2%2BBx%2BC where A=2, 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-%28-4%29+%2B-+sqrt%28+%28-4%29%5E2-4%282%29%28-3%29+%29%29%2F%282%282%29%29 Plug in A=2, B=-4, and C=-3


x+=+%284+%2B-+sqrt%28+%28-4%29%5E2-4%282%29%28-3%29+%29%29%2F%282%282%29%29 Negate -4 to get 4.


x+=+%284+%2B-+sqrt%28+16-4%282%29%28-3%29+%29%29%2F%282%282%29%29 Square -4 to get 16.


x+=+%284+%2B-+sqrt%28+16--24+%29%29%2F%282%282%29%29 Multiply 4%282%29%28-3%29 to get -24


x+=+%284+%2B-+sqrt%28+16%2B24+%29%29%2F%282%282%29%29 Rewrite sqrt%2816--24%29 as sqrt%2816%2B24%29


x+=+%284+%2B-+sqrt%28+40+%29%29%2F%282%282%29%29 Add 16 to 24 to get 40


x+=+%284+%2B-+sqrt%28+40+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


x+=+%284+%2B-+2%2Asqrt%2810%29%29%2F%284%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%284%2B2%2Asqrt%2810%29%29%2F%284%29 or x+=+%284-2%2Asqrt%2810%29%29%2F%284%29 Break up the expression.


x+=+%282%2Bsqrt%2810%29%29%2F%282%29 or x+=+%282-sqrt%2810%29%29%2F%282%29 Reduce.


So the solutions are x+=+%282%2Bsqrt%2810%29%29%2F%282%29 or x+=+%282-sqrt%2810%29%29%2F%282%29