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April 25, 2024, 04:02:49 am

Author Topic: Math methods units 1&2 help  (Read 453 times)  Share 

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Rose34

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Math methods units 1&2 help
« on: March 08, 2020, 05:23:53 pm »
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 A family of parabolas satisfies the rule y = ax^2 + 2x + a.
Express ax^2 + 2x + a in the form a(x + b)^2 + c for real numbers b and c.

Could someone please help me, I am stuck and have no idea how to start.

Thanks in advance!

sara.vce

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Re: Math methods units 1&2 help
« Reply #1 on: March 09, 2020, 01:58:50 pm »
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A family of parabolas satisfies the rule y = ax^2 + 2x + a.
Express ax^2 + 2x + a in the form a(x + b)^2 + c for real numbers b and c.

Here's what you could do. Hope it makes sense!

Complete the square for ax^2+2x+a
either use the formula:
= take out a as a common factor
= add 1/2*(2/a)^2 then subtract 1/2*(2/a)^2
= factorise into turning point form
or
use CAS:
menu>3>5: complete the square
completesquare(a x x^2 + 2 x x + a=0,x)
-> a(x+1/a)^2 + (a^2-1)/a