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Identify the number that needs to be added to both sides of the equation x2 + 4x = 96 to complete the square.?
Identify the number that needs to be added to both sides of the equation x2 + 4x = 96 to complete the square.
1. 2
2. 16
3. 4
4. –4
11 Answers
- adnansnazzyLv 41 decade agoFavorite Answer
Add 4.
Dear, I can tell you the exact way to make ANY quadratic a perfect square.
Here goes the steps for a quadratic equation ax^2+bx+c=0
1. Make the coefficient of x^2 equal to 1. This is done by taking the coefficent 'a' common from the whole quadratic.
2. Now add and subtract the square of half the coefficient of x i.e (b/2)^2
3. You can then guess it out yourself then the perfect square.
For your question:
Consider x^2 + 4x
The coefficient of x^2 is already equal to 1 so no worries.
Now add and subtract by (4/2)^2 which is equal to 4.
Hey, the second step is also called as "add the square of half the coefficient of x both sides of the equation" because when you subtract the required number it will become positive when it goes to the other side.
For more tips n tricks you can always contact me.
- Anonymous1 decade ago
4
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- DWReadLv 71 decade ago
x² + 4x = 96
Take the coefficient of the x term
(+4)
divide by two
(+4/2)
and square the result
(+4/2)²
This reduces to 4, so the answer is #3. But I never reduce it completely, (a) because it would have to be undone in the next steps, (b) you might forget which sign to use.
For example:
x² - 4x = 0
To complete the square, you add (-4/2)² to both sides. That can be reduced to 4, but then you lose the minus sign that you need later. Better to use (-2)²:
x² - 4x + (-2)² = 0 + (-2)²
(x-2)² = 4
- Anonymous1 decade ago
When you are completing the square, the number you add to the function is (b/2)^2
In this case b=4
(4/2)^2=4
Therefore your answer if choice 3
- Anonymous1 decade ago
the answer is 4.
then the lefh hand side will be x^2+4x+4 = (x+2)^2
and the right hand side will be 100 = 10^2.
- Anonymous1 decade ago
x2+4x=96
since
a2+b2+2ab=(a+b)2
so
(x)2+2(x)(2)+(2)2=96+(2)2
(x+2)2=96+4
(x+2)2=100
taking square root
x+2=10
x=10-2
x=8
hey its the rite answer why ur choices didnt include this answer