SOLUTION: Can someone please help me I seem to not be able to find the corresponding y values for x=-4,-3,-2,-1,0,1,2 if y=x^2+2x-15. Also can you show me how it is graphed. Thank you

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Can someone please help me I seem to not be able to find the corresponding y values for x=-4,-3,-2,-1,0,1,2 if y=x^2+2x-15. Also can you show me how it is graphed. Thank you      Log On


   

Question 150470This question is from textbook
: Can someone please help me I seem to not be able to find the corresponding y values for x=-4,-3,-2,-1,0,1,2 if y=x^2+2x-15. Also can you show me how it is graphed. Thank you This question is from textbook

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Table of Contents:


Jump to Table
Jump to Graph


In order to graph y=x%5E2%2B2x-15, we need to plot some points.


Let's find y when x=-4



y=x%5E2%2B2x-15 Start with the given equation.


y=%28-4%29%5E2%2B2%28-4%29-15 Plug in x=-4.


y=1%2816%29%2B2%28-4%29-15 Square -4 to get 16.


y=16%2B2%28-4%29-15 Multiply 1 and 16 to get 16.


y=16-8-15 Multiply 2 and -4 to get -8.


y=-7 Combine like terms.


So when x=-4, then y=-7.


So we have the point .


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Let's find y when x=-3:


y=x%5E2%2B2x-15 Start with the given equation.


y=%28-3%29%5E2%2B2%28-3%29-15 Plug in x=-3.


y=1%289%29%2B2%28-3%29-15 Square -3 to get 9.


y=9%2B2%28-3%29-15 Multiply 1 and 9 to get 9.


y=9-6-15 Multiply 2 and -3 to get -6.


y=-12 Combine like terms.


So when x=-3, then y=-12.


So we have the point .


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Let's find y when x=-2:


y=x%5E2%2B2x-15 Start with the given equation.


y=%28-2%29%5E2%2B2%28-2%29-15 Plug in x=-2.


y=1%284%29%2B2%28-2%29-15 Square -2 to get 4.


y=4%2B2%28-2%29-15 Multiply 1 and 4 to get 4.


y=4-4-15 Multiply 2 and -2 to get -4.


y=-15 Combine like terms.


So when x=-2, then y=-15.


So we have the point .


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Let's find y when x=-1:


y=x%5E2%2B2x-15 Start with the given equation.


y=%28-1%29%5E2%2B2%28-1%29-15 Plug in x=-1.


y=1%281%29%2B2%28-1%29-15 Square -1 to get 1.


y=1%2B2%28-1%29-15 Multiply 1 and 1 to get 1.


y=1-2-15 Multiply 2 and -1 to get -2.


y=-16 Combine like terms.


So when x=-1, then y=-16.


So we have the point .


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Let's find y when x=0:


y=x%5E2%2B2x-15 Start with the given equation.


y=%280%29%5E2%2B2%280%29-15 Plug in x=0.


y=1%280%29%2B2%280%29-15 Square 0 to get 0.


y=0%2B2%280%29-15 Multiply 1 and 0 to get 0.


y=0%2B0-15 Multiply 2 and 0 to get 0.


y=-15 Combine like terms.


So when x=0, then y=-15.


So we have the point .


----------------------------------------------------


Let's find y when x=1:


y=x%5E2%2B2x-15 Start with the given equation.


y=%281%29%5E2%2B2%281%29-15 Plug in x=1.


y=1%281%29%2B2%281%29-15 Square 1 to get 1.


y=1%2B2%281%29-15 Multiply 1 and 1 to get 1.


y=1%2B2-15 Multiply 2 and 1 to get 2.


y=-12 Combine like terms.


So when x=1, then y=-12.


So we have the point .


----------------------------------------------------


Let's find y when x=2:


y=x%5E2%2B2x-15 Start with the given equation.


y=%282%29%5E2%2B2%282%29-15 Plug in x=2.


y=1%284%29%2B2%282%29-15 Square 2 to get 4.


y=4%2B2%282%29-15 Multiply 1 and 4 to get 4.


y=4%2B4-15 Multiply 2 and 2 to get 4.


y=-7 Combine like terms.


So when x=2, then y=-7.


So we have the point .


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Now let's make a table of the values we just found.


Table of Values:





xy
-4-7


-3-12


-2-15


-1-16


0-15


1-12


2-7

Now let's plot the points:







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Graph:


Now draw a curve through all of the points to graph y=x%5E2%2B2x-15:


Graph of y=x%5E2%2B2x-15