Naked Science Forum
General Science => General Science => Topic started by: malylo on 10/11/2011 03:01:47
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Look at the function: f(x)=9x^2+12x+4. Please find x-intercept and y-intercept.
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y=9x2+12x+4
The Y-intercept is easy to calculate. Just set X=0.
y=9*02+12*0+4 = 4
To calculate the X-intercept, it is easiest to first factor the quadratic, in this case it is relatively easy, a perfect square.
y=(3x+2)(3x+2)
Now, set Y=0.
0=(3x+2)(3x+2)
So, either half (which is the same) must equal zero.
0=3x+2
3x=-2
x=-2/3