Answer:
-2x² + 15
Step-by-step explanation:
Step 1: Add like terms
4x² - 6x² = -2x²
-10x + 10x = 0
3 + 12 = 15
Step 2: Rewrite
-2x² + 15
N.b., this is copied from an answer I wrote for someone else.Thinking about the graph of y, the rate of change is zero whenever there is an extremum.
First, differentiate y.

Next, find the zeros of y' by factoring.

Now, we substitute these x-values into the
original equation to find the coordinates.
Y int is where the line crosses y axis....so it is 4.
the slope is -2
13 should be b and
14 is a because geometric mean to have a common ratio
(3x) + (x+60) = 180
4x + 60 = 180
Subtract 60 from both sides
4x = 120
Divide 4 from both sides
x = 30