Question

3×-5=16 and 3×=21

the first equation is a true statement for a certain value of x.

can you explain why the second equation must also be true for the same value of x?​

Answer 1

Explanation:

because we can also find out the value of x in second equation like this

3x=21

x=21/3

x=7

Answer 2

We conclude that x = 7 must be true for the second equation because it will also satisfy the second equation.

Explanation:

Given the first equation

• 3x-5 = 16

solving the equation

3x-5 = 16

adding 5 to both sides

3x-5+5 = 16+5

3x = 21 ∵ 3x = 21 is the 2nd equation

divide bothe sides by 3

3x/3 = 21/3

x = 7

Please notice that when simplifying 3x-5 = 16, the moment we reach 3x=21, we can determine that it represents the same equation.

In other words, whatever the value of x we will get, it will satisfy both equations.

Therefore, we conclude that x = 7 must be true for the second equation because it will also satisfy the second equation.

Verification:

Consider the 2nd equation

3x = 21

Put x = 7

3(7) = 21

21 = 21

Thus, it has been validated that when we conclude that x = 7 must be true for the second equation because it will also satisfy the second equation.