Here is the solution for you...
f(x) = ax^4 - 4x^2 + ax - 3
Therefore,
f(b) = ab^4 - 4b^2 + ab - 3
and
f(-b) = ab^4 - 4b^2 -ab - 3
Now f(b) - f(-b) = 2ab
You can see except ab all the terms would cancel out.
So answer is (B).
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codesnooker
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Its Very Simple
Here is the solution for you...
f(x) = ax^4 - 4x^2 + ax - 3
Therefore,
f(b) = ab^4 - 4b^2 + ab - 3
and
f(-b) = ab^4 - 4b^2 -ab - 3
Now f(b) - f(-b) = 2ab
You can see except ab all the terms would cancel out.
So answer is (B).
Here is the solution for you...
f(x) = ax^4 - 4x^2 + ax - 3
Therefore,
f(b) = ab^4 - 4b^2 + ab - 3
and
f(-b) = ab^4 - 4b^2 -ab - 3
Now f(b) - f(-b) = 2ab
You can see except ab all the terms would cancel out.
So answer is (B).
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resilient
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I follow you up to the last step. f(-b) = ab^4 - 4b^2 -ab - 3 but shouldnt it be
f(-b) = a(-b)^4 - 4(-b)^2 -a(-b) - 3 . WIth all this, I am getting 2ab-6. Thanks for the explanation. I am understanding much better and am stuck on last detail. Was very tired when studying last night!
f(-b) = a(-b)^4 - 4(-b)^2 -a(-b) - 3 . WIth all this, I am getting 2ab-6. Thanks for the explanation. I am understanding much better and am stuck on last detail. Was very tired when studying last night!
Appetite for 700 and I scraped my plate!
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bigfernhead
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Since f(b) – f(-b), you're negating the second half of the equation, and the -3 changes to a +3... and both of the 3 cancels to 0.resilient wrote:I follow you up to the last step. f(-b) = ab^4 - 4b^2 -ab - 3 but shouldnt it be
f(-b) = a(-b)^4 - 4(-b)^2 -a(-b) - 3 . WIth all this, I am getting 2ab-6. Thanks for the explanation. I am understanding much better and am stuck on last detail. Was very tired when studying last night!
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codesnooker
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Look the original equation is:resilient wrote:I follow you up to the last step. f(-b) = ab^4 - 4b^2 -ab - 3 but shouldnt it be
f(-b) = a(-b)^4 - 4(-b)^2 -a(-b) - 3 . WIth all this, I am getting 2ab-6. Thanks for the explanation. I am understanding much better and am stuck on last detail. Was very tired when studying last night!
f(x) = ax^4 - 4x^2 + ax - 3
So, when you replace x with -b in left hand side, the same you need to do at the right hand side.
f(b) = a(-b)^4 - 4(-b)^2 + a(-b) - 3
But the equation you mentioned is
Check here you have changed the sign of coefficient of term x. It should be +a instead of -a.resilient wrote: f(-b) = a(-b)^4 - 4(-b)^2 -a(-b) - 3 .
That's why you are getting incorrect answer.
I hope, now it must be clear to you.
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Jeff@TargetTestPrep
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Since f(x) = ax^4 - 4x^2 + ax - 3, we know:resilient wrote:If f(x) = ax^4 - 4x^2 + ax - 3, then f(b) - f(-b) will equal:
A. 0
B. 2ab
C. 2ab^4 - 8b^2 - 6
D. -2ab^4 + 8b^2 + 6
E. 2ab^4 - 8b^2 + 2ab - 6
f(b) = ab^4 - 4b^2 + ab - 3 and:
f(-b) = a(-b)^4 - 4(-b)^2 + a(-b) - 3 = ab^4 - 4b^2 - ab - 3 and finally:
f(b) - f(-b) = (ab^4 - 4b^2 + ab - 3) - (ab^4 - 4b^2 - ab - 3) = 2ab
Answer:B
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