+122 So, I came across a problem in my math book:
Find the coefficient of y^4 in the expansion of (2y - 5)^7
But I don't know how to do this correctly. My teacher looked over it and gave me a hint to solve the equation first, but there is no equation! I don't know how to get this, please, help. Thank you so much in advance!!!! I really do appreciate the help!
Find the coefficient of y^4 in the expansion of (2y - 5)^7
I couldn't expand that by hand, so I went to a math website. The answer I got there was
128y7 − 2240y6 + 16800y5 − 70000y4 + 175000y3 − 262500y2 + 218750y − 78125
So what is the coefficient of y4 according to that? Looks like it's –70,000
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+122 Thank you so so so much! May I know what math website you used? Thank you again!
I just asked google search to expand that expression. The top result was
https://www.mathway.com/popular-problems/Algebra/218494
When the page opened there was an example (x–2y)5 on the screen. I just clicked on each term and changed them to (2y–5)7 and then clicked the arrow out on the far right of that line.
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