QR 4 U from destroyer
Started by jdent
Remember that these problems require combinations to figure out individual terms. If the exponent is 'n', then there are 'n+1' terms in the final expansion - from the constant up to the nth power.
Each individual term is computed using a combination and knowledge of what the variables will be. The first term is (n choose 0) x^n y^0. The second term is (n choose 1) x^(n-1) y^1.
In general, the k-th term is given by (n choose [k-1] ) x^(n-k+1) y^(k-1).
If you want the 2nd term then k-1 = 2-1 = 1. You have n = 5.
(5 choose 1) x^4 y^1 = 5x^4y^1. But remember that x is really '3x' and y is really '-2y'.
5(3x)^4 (-2y)^1 = 5(81x^4)(-2y) = -810(x^4)👍
If you want the 3rd term then k-1 = 3-1 = 2. You still have n = 5.
(5 choose 2) x^3 y^2 = 10(x^3)(y^2). Again, x is really '3x' and y is really '-2y'.
10(3x)^3(-2y)^2 = 10(27x^3)(4y^2) = 1080(x^3)(y^2)
Now multiply those 2 out and you'll get -874,800(x^7)(y^3).
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Damn streetwolf beat me to it. I was working and just saw the post.
I have several A+ which count as 4.33 for Dental School.
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Yea but not on addsas thats why they have the grade converter so its standerdized for everyone including people who go to school with A+s and those who go to schools that only have A B with no plus or minus. It cant possibly be over 4 with the conversion!
Grab the next one 😉
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