Question

What’s the error and why?

Answer 1

step 2 is wrong ,

when positive 40 go in rhs than it will become negative and after subtraction it becomes 30 .

and when 5x comes from rhs to lhs than it will -ve that means it become -20x

now , on solving we'll get ;-

-20x = 30

x = 30/-20 => 3/-2 will your answer

hope it helps ;!

#Himanshu jha