Answer:
9$
Step-by-step explanation:
The way you undo multiplication is division. If the sweater costs 27$, you divide that by 3 to get a third of the cost.
4x+8x+12x+16x=5+10+30+40
4x+8x+12x+16x= 85
40x=85
x= 85/40
x=2.125
undefined
The x value does not change, which means it is a vertical line
Vertical lines have an undefined slope
we can check using
m = (y2-y1)/(x2-x1)
=(2- -2)/( -3 - -3)
= (2+2)/( -3+3)
4/0