235k views
2 votes
What is the value of x x-2/5 =7 what is the value of x

User GMe
by
8.2k points

2 Answers

0 votes
The answer could be 37
User Jskierbi
by
8.0k points
4 votes
Consider the puzzle:

"I have In mind a (secret) number. When I subtract 2/5 from this number I get 7. What is the number?"

To solve such puzzles we go backwards. We got 7 after we subtracted 2/5, so if we add 2/5 to 7, we get the secret number back.

Solving an equation is solving a puzzle about a secret number, which we call "x" instead of saying "something", all the time.

going backwards, means adding, if we subtracted, or dividing, if we multiplied.


So, to solve
x- (2)/(5)=7, we just need to add 2/5 back to x:


x- (2)/(5)=7


x- (2)/(5)+(2)/(5)=7+(2)/(5)


x=7+(2)/(5)

to add 7 and 2/5, multiply 7 by 5/5

7+2/5=7.(5/5)+2/5=35/5+2/5=37/5



Thus x= 37/5



User Jonauz
by
7.7k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories