Question

Solve and verify the result:-
4x + 7 = 15

Answer 1

HINT:-
We are going to use the transposition method to solve this question, and to find the value of x.

Transposition method means that we will shift the constants or variables from one side of the equation to the other side of the equation. And when we will transpose constants and variables, the operation of the constant or the variable will change.

For example:-

5x + 8 = 33

Complete step-by-step answer:

Here we can see that the operation of the constant ‘8’ is addition. When we transpose it to the other side of the equation, then the operation of ‘8’ will become subtraction, i.e., change in the sign of the constant ‘8’ will take place.

5x = 33 – 8

5x = 25

Here we can see that the operation of the constant ‘5’ is multiplication. When we transpose it to the other side of the equation, then the operation of ‘5’ will become division, i.e., change in the operation of the constant ‘5’ will take place.

x = \[\dfrac{25}{5}\]

x = 5


Let us now solve the question.

4x + 7 = 15

Here we can see that the operation of the constant ‘7’ is addition. When we transpose it to the other side of the equation, then the operation of ‘7’ will become subtraction, i.e., change in the sign of the constant ‘7’ will take place.

4x = 15 – 7

4x = 8

x = \[\dfrac{8}{4}\]

x = 2

Hence, the value of ‘x’ is 2.

Let us now verify this.

4x + 7 = 15

4 2 + 7 = 15

8 + 7 = 15

15 = 15

Hence, verified

NOTE:-

One must do all the calculations in this question very carefully.

Also not only in this question, the students must be very careful while solving any such questions as if there is any mistake in the calculus, then the answer can come out to be wrong.