Of the 10 possible molds, only two can have a base that is a square. That is, a base where the all 4 sides are equal. In this case, you can make the molds:
1,1,28 ; where the base is a 1x1 square with height 28 cm.
and
2,2,7 ; where the base is a 2x2 square with height 7 cm.
If she wants to frame a square painting with an area of 400 square inches, all you would have to do is to find the square root of 400, which is 20. Thus, each side is 20 inches long.
If you have to set an equation up, it would simply be:
First of all you know it wiill be a positive slope as both the rise and the run are negative. a negative divided by a negative equals a positive. so you can plot the points (2,3) and (-2,-3) as they will be points on this line. next you take a straight line and place it so that both points are intercepted. then extend the line outwards.
An expression that can be used to represent the increase in temperature is:
23-(-8)
If you simplify it you get:
23+8
31