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If g(x) = x^2 – 2x – 6 and h(x) = 2x^2 – 5x + 2 find (h – 9) (-2)

User Chrk
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Answer: (h-g)(-2)=18

Explanation:

(h – g) (-2) means the same as subtracting h(-2) and g(-2). Since we are given h(x) and g(x), we can use them to solve. There are two ways to solve. One is to find h(-2) and g(-2), and then subtract them. Another way is to do (h-g)(x), then plug in x=-2. I will show both methods.

Method 1

h(-2)=2(-2)²-5(-2)+2 [exponent]

h(-2)=2(4)-5(-2)+2 [multiply]

h(-2)=8+10+2 [add]

h(-2)=20

g(-2)=(-2)²-2(-2)-6 [exponent]

g(-2)=4-2(-2)-6 [multiply]

g(-2)=4+4-6 [add then subtract]

g(-2)=2

(h-g)(-2)=20-2 [subtract h(-2) and g(-2)]

(h-g)(-2)=18

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Method 2

(h-g)(x)=2x²-5x+2-(x²-2x-6) [distribute -1]

(h-g)(x)=2x²-5x+2-x²+2x+6 [combine like terms]

(h-g)(x)=x²-3x+8

(h-g)(-2)=(-2)²-3(-2)+8 [plug in x=-2, exponent]

(h-g)(-2)=4-3(-2)+8 [multiply]

(h-g)(-2)=4+6+8 [add]

(h-g)(-2)=18

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Now, we know that (h-g)(-2)=18. We confirmed this with both methods.

User Cristian Todea
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