<span>Given that f(x) = 2x + 5 and g(x) = x − 7
</span>f(g(x)) = 2(x − 7) + 5
f(g(x)) = 2x - 14 + 5
f(g(x)) = 2x - 9
when x = −3 , f(g(-3)) = 2(-3) - 9 = - 6 - 9 = -15
Answer
<span>A. −15</span>
Perimeter is the sum of all three sides so in this case x+(3x+2)+(3x+2).
They also gave us the perimeter which is 39 so
39= x+(3x+2)+(3x+2)
Simplify so 39=7x+4. [x+3x+3x=7x and 2+2=4]
Then get x by itself so subtract 4 from both sides.
35=7x
Then divide both sides by 7 to get x by itself.
Which leaves us with
X=5
In linear models there is a constant additve rate of change. For example, in the equation y = mx + b, m is the constanta additivie rate of change.
In exponential models there is a constant multiplicative rate of change.
The function of the graph seems of the exponential type, so we can expect a constant multiplicative exponential rate.
We can test that using several pair of points.
The multiplicative rate of change is calcualted in this way:
[f(a) / f(b) ] / (a - b)
Use the points given in the graph: (2, 12.5) , (1, 5) , (0, 2) , (-1, 0.8)
[12.5 / 5] / (2 - 1) = 2.5
[5 / 2] / (1 - 0) = 2.5
[2 / 0.8] / (0 - (-1) ) = 2.5
Then, do doubt, the answer is 2.5
