solve 3x+7=5x+2(3-x)+1

Question

why would both x=x and 7=7 both be correct answers to this equation?

Answer 1

This is an identity

3x+7=5x+2(3-x)+1
3x+7=5x+6-2x+1=3x+7

it is true for all values of x

Answer 2

Hi PJ;

 

3x+7=5x+2(3-x)+1

Let's distribute 2(3-x)...

3x+7=5x+6-2x+1

Let's combine like terms...

3x+7=3x+7

 

Let's subtract 7 from both sides...

-7+3x+7=3x+7-7

3x=3x

Let's divide both sides by 3...

3x/3=3x/3

x=x

 

3x+7=3x+7

Let's subtract 3x from both sides...

-3x+3x+7=3x+7-3x

7=7