SOLUTION: 2x^2-7x=4

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Question 119129: 2x^2-7x=4
Found 2 solutions by jim_thompson5910, edjones:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2-7x=4 Start with the given equation


2x%5E2-7x-4=0 Subtract 4 from both sides.


%28x-4%29%282x%2B1%29=0 Factor the left side (note: if you need help with factoring, check out this solver)



Now set each factor equal to zero:
x-4=0 or 2x%2B1=0

x=4 or x=-1%2F2 Now solve for x in each case


So our answer is
x=4 or x=-1%2F2


Notice if we graph y=2x%5E2-7x-4 we can see that the roots are x=4 and x=-1%2F2 . So this visually verifies our answer.


+graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C0%2C+2x%5E2-7x-4%29+

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
2x^2-7x=4
2x^2-7x-4=0
2*-4=-8 multiply the 1st and last numbers.
What 2 factors of -8 when added equal -7? Ans.: -8 and 1
2x^2-8x+x-4=0
2x(x-4)+(x-4)=0 factoring by grouping.
(2x+1)(x-4)=0
.
2x+1=0
2x=-1
x=-1/2
.
x=4
.
Check:
2*-.5^2-7*-.5=4
2*.25+3.5=4 true
.
2*4^2-7*4=4
32-28=4 true
.
Ed