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