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Which function has an x-intercept of 4?

A. f(x)=-3x+16/4
B. f(x)=(x+4)(x-3)
C. f(x)=x²+2x-8
D. f(x)=x-4

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the answer is c .
ill explain it.
step one:f(x)=x²+2x-8d ---> you have to do exponents first so you multiply x and x.

step two:f(x)=2x+2x-8d ---> when you multiply the 2 x's together you get 2x. then you must add together 2x and 2x.

step three:f(x)=4x-8d --->your answer then becomes 4x and that is what gives you your x intercept :) hopefully I helped ^.^
therefore the x intercept is 4

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Sorry but this is wrong.
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The answer to this is f(x) = x?+2x-8. To arrive at this, you have to multiply. This will give you f(x)=2x+2x-8d. Add the like terms together to get f(x) = 4x ? 8d.

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Sorry but this is wrong.
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The answer is D.
You can do this 2 ways.
1) Plug 4 into each equation. If you get 0 that is the right one.
1. -3(4)+16/4 = -12+4 = -8. NO
2. (4+4)(4-3) = (8)(1) = 8. NO
3. (4^2)+2(4)-8 = 16+8-8 =16 NO
4. 4-4 = 0 YES
2) Solve each equation for x. If you get x = 0 that is right one.

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