Welcome to Westonci.ca, where finding answers to your questions is made simple by our community of experts. Join our Q&A platform and connect with professionals ready to provide precise answers to your questions in various areas. Get quick and reliable solutions to your questions from a community of experienced experts on our platform.

Complete the square for [tex]$2x^2 - 4x = 14$[/tex].

A. [tex]$(2x - 1)^2 = 15$[/tex]
B. [tex][tex]$(x - 1)^2 = 8$[/tex][/tex]
C. [tex]$(2x - 2)^2 = 30$[/tex]
D. [tex]$(x + 1)^2 = 8$[/tex]


Sagot :

Let's solve the given equation [tex]\(2x^2 - 4x = 14\)[/tex] by completing the square.

1. Start with the given equation:
[tex]\[ 2x^2 - 4x = 14 \][/tex]

2. Move the constant term to the left side to set the equation to zero:
[tex]\[ 2x^2 - 4x - 14 = 0 \][/tex]

3. Factor out the coefficient of [tex]\( x^2 \)[/tex] from the terms that involve [tex]\( x \)[/tex]:
[tex]\[ 2(x^2 - 2x) = 14 \][/tex]

4. To complete the square, we need to add and subtract the same value inside the parenthesis. The term to complete the square is found by taking half the coefficient of [tex]\( x \)[/tex] (which is [tex]\(-2\)[/tex]), and squaring it:
[tex]\[ \left(\frac{-2}{2}\right)^2 = 1 \][/tex]

5. Add and subtract this square term inside the parenthesis:
[tex]\[ 2(x^2 - 2x + 1 - 1) = 14 \][/tex]

6. This simplifies to:
[tex]\[ 2((x - 1)^2 - 1) = 14 \][/tex]

7. Distribute the 2 across the terms inside the parenthesis:
[tex]\[ 2(x - 1)^2 - 2 = 14 \][/tex]

8. Move the constant term [tex]\(-2\)[/tex] to the right side:
[tex]\[ 2(x - 1)^2 - 2 + 2 = 14 + 2 \][/tex]

9. Simplify the equation:
[tex]\[ 2(x - 1)^2 = 16 \][/tex]

10. Divide by 2 to isolate the square term:
[tex]\[ (x - 1)^2 = 8 \][/tex]

Thus, the equation simplifies to the form:
[tex]\[ (x - 1)^2 = 8 \][/tex]

So, the correct answer is:
[tex]\[ \boxed{B} \][/tex]