SOLUTION: Hello everyone, Im struggling with some graphing problems and would greatly appreciate some help.I need to find the y-intercept, the x intercepts and any turning point of the follo

Algebra ->  Graphs -> SOLUTION: Hello everyone, Im struggling with some graphing problems and would greatly appreciate some help.I need to find the y-intercept, the x intercepts and any turning point of the follo      Log On


   

Question 200492: Hello everyone, Im struggling with some graphing problems and would greatly appreciate some help.I need to find the y-intercept, the x intercepts and any turning point of the following function: y = -2x -7x +4
Any help and explanations would be great.
Thanks, -NIck
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
y = -2x -7x +4
y=-9x+4
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+-9x+%2B4%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, -9x +4).
Solution (4/9,4).
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y=2x^2-3x-1
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+2x%5E2+-3x+-1+%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, 2x^2 -3x -1).
y=-1
Using the quadratic equation x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ we get:
x=(3+-sqrt[-3^2-4*2*-1])/2*2
x=(3+-sqrt[9+8)/4
x=(3+-sqrt17)/4
x=(3+-4.123)/4
x=(3+4.123)/4
x=7.123/4
x=1.78 ans.
x=(3-4.123)/4
x=-1.123/4
x=-.28 ans.
Answer(1.78 & -.28,-1).