Philip P. answered • 01/25/18

Affordable, Experienced, and Patient Algebra Tutor

^{2}+bx+c).

Ben Z.

asked • 01/25/18Please tell me what the equation is!!

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Philip P. answered • 01/25/18

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Use the factored form:

y = a(x+1.6)(x+3.2)

To find the value of a, plug in (0,25.6):

25.6 = a(0+1.6)(0+3.2)

Solve for a. Once you have the value of a, multiply the factored form out to convert to standard form (y = ax^{2}+bx+c).

Mark M. answered • 01/25/18

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vertex (-2.4, k) halfway between -1.6 and -3.2

y = (x + 2.3)^{2} + k vertex form

0 = a(-1.6 + 2.3)^{2} + k

0 = a(-3.2 + 2.3)^{2} + k

Solve for a

Substitute "a" and solve for k.

Arthur D. answered • 01/25/18

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the graph passes through (-1.6,0) and (-3.2,0)

this means f(-1.6)=0 and f(-3.2)=0

therefore f(x)=(x+1.6)(x+3.2)

f(x)=x^2+4.8x+5.12

f(x)=k(x^2+4.8x+5.12) also passes through the above two points

f(x) passes through (0,25.6)

therefore 25.6=k(0^2+4.8*0+5.12)

25.6=k(5.12)

k=25.6/5.12

k=5

y=5(x^2+4.8x+5.12)

y=5x^2+24x+25.6

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