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10 votes
10 votes
4x^2+8x-12 in vertex form

User Nightwatch
by
2.7k points

2 Answers

26 votes
26 votes

Answer:

y = 4 (x + 1)² - 16

Explanation:

Step 1: Equation at the end of step 1

(2²x²+8x)-12

Step 2:

Step 3: Pulling out like terms

Pull out like factors :

4x² + 8x - 12 = 4 • (x² + 2x - 3)

Trying to factor by splitting the middle term

Factoring x²+ 2x - 3

The first term is, x²

its coefficient is 1 .

The middle term is, +2x its coefficient is 2 .

The last term, "the constant", is -3

Step-1 : Multiply the coefficient of the first term by the constant 1 • -3 = -3

Step-2 : Find two factors of -3 whose sum equals the coefficient of the middle term, which is 2 .

-3 + 1 = -2

-1 + 3 = 2 That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -1 and 3

x² - 1x + 3x - 3

Step-4 : Add up the first 2 terms, pulling out like factors :

x • (x-1)

Add up the last 2 terms, pulling out common factors :

3 • (x-1)

Step-5 : Add up the four terms of step 4 :

(x+3) • (x-1)

Which is the desired factorization

Final result :

Final result :

4 • (x + 3) • (x - 1)

Now convert to vertex form:

y = 4 (x + 1)² - 16

User Stackit
by
2.8k points
23 votes
23 votes
The answer in vertex form is y=4(x+1)^2 -16
User Morten Fast
by
2.4k points
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