193k views
3 votes
Follow the process of completing the square to solve 2x2 + 8x - 12 = 0. How will the left side of the equation factor in step 5?

A. (2x + 32)2

B. (4x + 8)2

C. (4x + 16)2

User Jon Jaques
by
8.6k points

2 Answers

3 votes

Complete the square to solve
2x^2 + 8x - 12 = 0.

Soooooooo,
(4x + 8)^2 is your answer. :)

User SmacL
by
8.2k points
1 vote
2x^2+8x-12=0
with form
ax^2+bx+c=0

move c to the other side
2x^2+8x=12

x^2 is multiplied -> divide equation by 2
x^2+4x=6

complete square:
divide b=4 by 2
4*1/2=2

square 2
2^2=4

add 4 to both sides
x^2+4x=6
x^2+4x+4=6+4
x^2+4x+4=10

transform to polynom
(x+2)^2=10

this left side is option B multiplied by a factor of 16 and therefore equal:
(4x + 8)^2
(4*4)x^2+(4*2*8)x+8*8
16x^2+64x+64
x^2+4+4

bonus: calculate root
x+2=+/-sqrt(10)
x=-2+/-sqrt(10)


so it is option B
User Kyndigs
by
8.4k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories