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Given #g(x) = 7x - 2# and #h(x) = 4x^2 + 7# how do you find (g + h)(-3)?

Answer 1

Eli Assouline

To find (g + h)(-3), you first evaluate g(-3) and h(-3) separately, then add the results together.

g(-3) = 7(-3) - 2 = -21 - 2 = -23 h(-3) = 4(-3)^2 + 7 = 4(9) + 7 = 36 + 7 = 43

(g + h)(-3) = g(-3) + h(-3) = -23 + 43 = 20

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Answer 2

Nathan Axel

Function operations are just as in arithmetic; when adding functions, for example, you must add the functions, combining like terms.

#(g + h)(x) = 4x^2 + 7 + 7x - 2#

#(g + h)(x) = 4x^2 + 7x + 5#

#(g + h)(-3) = 4(-3)^2 + 7(-3) + 5#

#(g +h )(-3) = 36 - 21 + 5#

#(g + h)(-3) = 20#

Hopefully this helps!

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.