Lets say we have a quadratic equation:
3x^2 + x + 0 = 0
Now, since if we add or subtract 0 from something, the original value stays the same, which means we can write the equation as 3x^2 + x = 0 and ignore the “+0”.
In these kinds of equations, you /can/ use the quadratic formula, but theres a much quicker way. If we factor 3x^2 + x, we get x(3x + 1) = 0. Here, x has two possible values — since the result of the multiplication is 0, that means that either one expression or the other must equal 0. In essence:
If x(3x+1) = 0 then x = 0 or 3x+1 = 0
One of the solutions is that x = 0. Lets find the other.
3x+1=0
3x= -1
x = -1/3
So x1 = 0 and x2 = -1/3. So basically you solve these equations using basic factorization. :)
What you do is move the equation around so the 12 -4.5x would now turn into y=-4.5x+12
11) x-intercept: 12
y-intercept: 8
12) x-intercept: -18
y-intercept:-16
13) x-intercept: 6
y-intercept:10
Sorry I can't graph it for you but here are the equations in the slope-intercept form
11)y=-2/3x+8
12)y=-8/9x-16
13)y=-5/3x+10
2 x 2 + 9x + 8 = 0
4 + 9x + 8 = 0
12 + 9x = 0 (subtract 12 from each side)
9x = -12 (divide by 9 on each side)
x = -12/9
