It could sometimes be proportional. The reasoning here is that if all the items have different prices it won't be, however if the items you are ordering all have the same price they will be!
Remember you can do anything to an equation as long as you do it to both sides
4x-5=4x+10
minus 4x both sides
-5=10
false
no solution
The answer is 4.29 is the percent
Since our line is perpendicular to this line, the slope of
our line is the negative reciprocal of 1/4, which is -4/1.
Remember, negative reciprocal is just a fancy way
of saying flip the fraction and change the sign.
So the slope of our line is -4/1 and we use this slope along
with our given point to write the equation of our line.
Start with the point-slope formula.
Y - y1 = m(x - x1).
~Substitute
Y - -2 = -4/1(x - 5).
Minus a negative is plus a positive.
Y + 2 = -4/1x + 20.
Subtract 2 from both sides.
Y = -4/1x + 18
So, our answer is C.
Recall the inverse function theorem: if f(x) has an inverse, and if f(a) = b and a = f⁻¹(b), then
f⁻¹(f(x)) = x ⇒ (f⁻¹)'(f(x)) • f'(x) = 1 ⇒ (f⁻¹)'(f(x)) = 1/f'(x)
⇒ (f⁻¹)'(b) = 1/f'(a)
Let b = 10. Then pick the function f(x) such that f(a) = 10 and f'(a) = -8 for some number a.
