WAEC Mathematics 2011 Paper

x² - 3x = 7

x² - 3x - 7 = 0

What can you add to both sides of the equation to give the same value of y = x² - 3x - 3

The number is 4

x² - 3x - 7 + 4 = 4

x² - 3x - 3 = 4

but y = x² - 3x - 3

y = 4; So are y = 4 draw a line parallel to x axis, to cut or intersect the graph. At these points look down to see the corresponding values on x axis

This give -1.55 and 4.55