Find the quadratic function y=ax^2 + bx + c whose graph passes through the given points. ​(-3​,37​), ​(2​,-8​), ​(-1​,13)

Respuesta :

The quadratic function is [tex]y=1x^{2} + (-8)x + 4[/tex]

Step-by-step explanation:

The quadratic function given is [tex]ax^{2} + bx + c=y[/tex]

and same quadratic function is passes through (-3​,37​), ​(2​,-8​), ​(-1​,13)

Replacing points one by one

we get,

For (-3​,37​) :

[tex]a(-3)^{2} + b(-3) + c=37[/tex]

[tex]9a + -3b + c=37[/tex] = equation 1

For (2​,-8​) :

[tex]a(2)^{2} + b(2) + c=(-8)[/tex]

[tex]4a + 2b + c=(-8)[/tex] =  equation 2

For ​(-1​,13)

[tex]a(-1)^{2} + b(-1) + c=(13)[/tex]

[tex]a + -1b + c=13[/tex] = equation 3

Solving the linear equation to get values of a,b,c

Subtract equation 2 with equation 3

we get,[tex](4a + 2b + c)-(a + -1b + c)=(-8)-13[/tex]

[tex](3a + 3b )=(-21)[/tex]

[tex](a + b )=(-7)[/tex]  = equation 4

Now, Subtract equation 1 with equation 2

we get,[tex](9a + -3b + c)-(4a + 2b + c)=(37)-(-8)[/tex]

[tex](5a - 5b )=(45)[/tex]

[tex](a - b )=(9)[/tex]  = equation 5

Now, Add equation 4 with equation 5

we get,[tex](a + b)+(a - b)=(-7)+(9)[/tex]

[tex](2a - 0b )=(2)[/tex]

[tex](a)=1[/tex]  

Replacing value of a in equation 5

[tex](a - b )=(9)[/tex]

[tex](1 - b )=(9)[/tex]

[tex](b)=(-8)[/tex]

Replacing value of a and b in equation 1

[tex]9a + -3b + c=37[/tex]

[tex]9(1) + -3(-8) + c=37[/tex]

[tex]9 + 24 + c=37[/tex]

[tex] c=4[/tex]

Thus,

The quadratic function [tex]y=1x^{2} + (-8)x + 4[/tex]

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