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Shannon20150
Factor 2x4 - 20x2 - 78. 2(x2- 3)(x2- 13) ***** 2(x2+ 3)(x2- 13) 2(x2- 3)(x2+ 13) I think is right ****
help me @FibonacciChick666
I would like you to please first try and check your answer before I try the problem. You are going to do this by using the FOIL method.
I did that's y I asked if its right
alrighty good, I'm working on it right now
ok so only one of your answers is correct. let's go through the process together.
First factor out the 2 to get 2(x^4-10x^2-39) Replace any x^2 value with the variable a, so x^4 becomes a^2 because x^2 squared is x^4. You just do this to take the place of any x^2 s to make it easier, if that makes sense. So 2(a^2-10a-39). Then you can do regular factoring. 3 and -13 multiply to become -39, and 3-13=10. So The equation would become \[2(a+13)(a-3)\] Then change the a's back into x^2. So the answer is \[2(x ^{2}+3)(x ^{2}-13)\] So the answer is the second one.
So the first thing that we want to do is pull out any like terms. What does each term in the expression have in common?
okay I need help again
ok, does the term (-78) contain an \[x ^{2}\]
You can check your work by multiplying the factors back together using either the box method or FOIL. \[2(x ^{4}-13x ^{2}+3x ^{2}-39)\]Combine like terms to get \[2(x ^{4}-10x ^{2}-39)\]Then distribute the 2 \[2x ^{4}-20x ^{2}-78\]You know your answer is correct if it is the same as the original equation.
will u help me in another problem @rosedewittbukater
let's try a different approach. can you divide -78 by x^2 without leaving a remainder?
okay I posted it already
ok so what is -78 divided by x^2 ?
Where did you post it
-39 is -78 divided by only 2 but think about the other terms listed do they also divide by 2?
She's trying to ask what number or value can be divided out of every single part of the equation. There's no x^2 in 78 so the only common number that all of the numbers can be divided by is 2.
let's try a slightly simplified example if you have the equation: \[2x+2\] What number is common to both terms?