Question

challenge for question number 6
solution needed
*image in comments

Answer 1

@ganeshie8

Answer 2

I'm thinking b or c

Answer 3

@dan815

Answer 4

ugghh
just plug into wolfram

Answer 5

@dan815 that means u cannot do it :P

Answer 6

i need solution

Answer 7

plz its too easy to do

Answer 8

Substitution

Answer 9

I think instead of promoting wolfram, we must teach them how to do this mentally and without using any software. -___-