The descriminant is b^2-4ac so for 26 it would be -5^2 - 4 (1) (7). The quadratic formula is -B plus or minus the square root of b squared minus 4ac over 2a
So you do $90 times .40 because 40%=.40 then next you set up your problem
90x.40=36
In total the sales price is $36
I need the full question and not just a graph to correctly answer this...0
I assume you mean the inverse function. To find the inverse function of a given function, start from the expression 
and solve for x:
Multiply both sides by 4:
Divide both sides by 3:
So this is the inverse function.
