Math, asked by CONAN4869, 1 year ago

find the coefficient of a^3 is the expansion of (2a-5)^3

CONAN4869: plz help me

QGP: Okay, Now it is clear

CONAN4869: thx

QGP: Which standard are you though?

CONAN4869: i am 9th

CONAN4869: and u

QGP: Oh okay. I was thinking of answering with an 11th std method. [I passed 12th this year]

CONAN4869: oh cool no problem

adhikarisandeep: hey answer it!!

adhikarisandeep: i am in 11th by the way!!

Answers

Answered by QGP

$\textrm{The identity is } \\ (x-y)^3 = x^3 - y^3 - 3xy(x-y) = x^3 - y^3 - 3x^2y + 3xy^2 \\ \\ Here \, \, (2a-5)^3 = (2a)^3 - (5)^3 - 3(2a)(5)(2a-5) = 8a^3-125-60a^2+150\\ \\ \textrm{Clearly, coefficient of } a^3 \, is \, 8 \\ \\ \textrm{So, answer is 8 }$

QGP: Okay. Now the code is perfect. It should be visible perfectly now

CONAN4869: yes thank you very much for helping

Answered by poonamvedh

Answer:

Step-by-step explanation:

Expanded (2a-5)^3

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