The answer to this questing is 100, because (23 x 2) + (18 x 3) = 100
I think you definitely need technology and objects to represent the data
1. use the equation y -y1 = m(x-x1)
2. (-6,-4) is x1,y1 and (4,-6) is x2,y2
3. y-(-4) = m(x-(-6)
m is the gradient, 10/10, which is 1. make two negatives into a positive.
4. y+4 = x+6
therefore the equation of the lines is y = x+2
substitute the points back into the equation to double check.
