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PLEASE HELP ASAP. IT'S TIMED. If your quadratic equation had no numbers and was represented by ax²+bx=c. Tell me step by step what I should do to complete the square. PLEASE HELP ASAP.

User Reflexiv
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1 Answer

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Answer:

(x+ (b/2a))^ 2 = (b/2a) ^2 + c/a

Explanation:

ax²+bx=c

first we know the form of a square

(x+a)^2 = x^2 + 2ax + a^2

we have to write the given ax²+bx=c in the above form

for that we bring c on LHS

for the we subtract c from both sides

ax²+bx -c =c - c

=> ax²+bx - c = 0

now we see that in x^2 + 2ax + a^2 , term x^2 does not have any coefficient,

so in our equation we get rid of coefficient a from ax²+bx - c = 0

for that we divide both LHS and RHS by a

(ax²+bx - c)/a = 0/a

x²+bx/a - c/a = 0

now we have to write (b/a)x in form of 2ax

for we divide and multiply (b/a)x by 2

thus we have

x²+2 (b/2a)x - c/a = 0

now comparing above equation with x^2 + 2ax + a^2

we see that 2ax is same 2 (b/2a)x

thus (b/2a) is same as a in standard form of quadratic equation x^2 + 2ax + a^2

now we have to get a^2

as (b/2a) is same as a

we add and subtract square of (b/2a) on LHS

x²+2 (b/2a)x - c/a + (b/2a) ^2 - (b/2a) ^2 = 0

rearranging it

x²+2 (b/2a)x + (b/2a) ^2 - (b/2a) ^2 -c/a = 0

=> x^2 + (b/2a)x + (b/2a) ^2 -(b/2a) ^2 -c/a = 0

=> (x+ (b/2a))^ 2 - ((b/2a) ^2 + c/a ) = 0

=> (x+ (b/2a))^ 2 = (b/2a) ^2 + c/a answer

User DKnight
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