Answer:
f(x) = (x + 6)² - 29
Step-by-step explanation:
Given
f(x) = x² + 12x + 7
To complete the square
add/subtract ( half the coefficient of the x- term )² to x² + 12x
x² + 2(6)x + 36 - 36 + 7
= (x + 6)² - 29, thus
f(x) = (x + 6)² - 29
Choice A is one of the answers. Nice work. This is because x+x+x turns into 3x.
Choice D is the other answer because 2(x+1) + x = 2x+2+x = 3x+2. You can find this through trial and error. Or you could graph y = x+x+x+2 and y = 2(x+1)+2 to find that they are the same exact identical diagonal line. A non-graph approach would be to set up a table of values to see that the two tables are identical.
ANSWER
Or
EXPLANATION
Let us find the gradient of the line:
by rewriting it in the slope intercept form.
We divide through by 4 now;
This is now in the form;
where
is he slope.
This implies that the slope of the line that is perpendicular to this line will be the negative reciprocal of .
Thus the perpendicular line has slope,
.
Let the perpendicular line have equation,
When we substitute the slope we have;
We substitute the point. 
to find c.
We substitute c to obtain;
Or
The answer is most likely C. Cubic meters.
