To find the zeros of a function, you can use a graph and find where the function goes through the x-axis. If you cannot use a graph you can factor the function and solve for x like this:
9x^2 + 6x - 8 = (3x - 2)(3x + 4)
Now solve for x:
3x - 2 = 0
3x = 2
x = 2/3
3x + 4 = 0
3x = -4
x = -4/3
So the zeros are x = 2/3 ; -4/3
