For number 7, you're asked for an equation that you would then use to solve for the variable, x. It is given that the interior angle of the triangle has a sum of 180. Therefore, you know that 180= 3x+44+x+20. This would be your equation. Now we solve for the x value.
180= 3x+44+x+20
180=4x+64
180-64= 4x+64-64
116=4x
116/4=4x/4
29 = x