Question 1205293
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Answer:  <font color=red size=4>6</font>



I'll show two methods.
Method 1
(f + g)(x) = f(x) + g(x)
(f + g)(x) = (4-5x) + (-x^2+2x)
(f + g)(x) = -x^2 - 3x + 4
(f + g)(-1) = -(-1)^2 - 3(-1) + 4
(f + g)(-1) = -1 - 3(-1) + 4
(f + g)(-1) = -1 + 3 + 4
(f + g)(-1) = <font color=red>6</font>



Method 2
f(x) = 4 - 5x
f(-1) = 4 - 5(-1)
f(-1) = 4 + 5
f(-1) = 9
g(x) = -x^2+2x
g(-1) = -(-1)^2+2(-1)
g(-1) = -1+2(-1)
g(-1) = -1-2
g(-1) = -3
(f + g)(-1) = f(-1) + g(-1)
(f + g)(-1) = 9 + (-3)
(f + g)(-1) = 9 - 3
(f + g)(-1) = <font color=red>6</font>



There are many online tools you can use to verify the answer. 
In Desmos you can type the functions in as given.
Make sure to type x^2 to mean {{{x^2}}}
Once functions f(x) and g(x) are set up, you can then have Desmos compute f(-1)+g(-1)
<a href="https://www.desmos.com/calculator/fn0hcid0bq">https://www.desmos.com/calculator/fn0hcid0bq</a>
Refer to the calculations in the left-side panel.
I recommend using Desmos as a way to verify the answer, rather than do all of your homework for you. 
GeoGebra is another similar and very useful tool that you could use.
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