Question

Select all equations where x=3 is a solution

a x+4=7
b x/9 =3
c 5-x=2
d 8x=32
e x-10=7

Answer 1

The goal of this problem is to determine all of the equations where x = 3 is a solution and this can be done by simply inputting the value 3 into any variable x that is seen into the expression. After, inputting the value we would simplify both sides and compare them. If the expression evaluates to true then x = 3 is a solution of the equation but if it evaluates to false then x = 3 is not a solution of the equation.

Equation #1

• 
  `x+4=7`

• 
  `3 + 4 = 7`

• 
  `7 = 7`

After inputting the value 3 into x, we added 4 to it and the final result that we got on the left side was 7 which was equal to the right side (7). Therefore, x = 3 is a solution of the first equation.

Equation #2

• 
  `(x)/(9) = 3`

• 
  `(3)/(9) = 3`

• 
  `(1)/(3) \\e 3`

After inputting the value 3 into x, we did 3 divided by 9 and the final result that we got on the left side was 1/3 which was not equal to the right side (3). Therefore, x = 3 is not a solution of the second equation.

Equation #3

• 
  `5-x = 2`

• 
  `5 - 3 = 2`

• 
  `2 = 2`

After inputting the value 3 into x, we subtracted 3 from 5 and the final result that we got on the left side was 2 which was equal to the right side (2). Therefore, x = 3 is a solution of the third equation.

Equation #4

• 
  `8x = 32`

• 
  `8(3) = 32`

• 
  `24 \\e 32`

After inputting the value 3 into x, we multiplied 3 by 8 and the final result that we got on the left side was 24 which was not equal to the right side (32). Therefore, x = 3 is not a solution of the fourth equation.

Equation #5

• 
  `x - 10 = 7`

• 
  `3 - 10 = 7`

• 
  `-7 \\e 7`

After inputting the value 3 into x, we subtracted 10 from 3 and the final result that we got on the left side was -7 which was not equal to the right side (7). Therefore, x = 3 is not a solution of the fifth equation.

Therefore, the only expressions that had a solution of x = 3 was the first and third equations since the final expression evaluated to true.