Tom is given the equation 10x+15=20

Question

10

+
15
=
20
 to solve. He says the solution is  12
1
2
. Which reason justifies his solution?(1 point)
Responses

Tom says that to solve the equation you first divide by 10 and then subtract 15.
Tom says that to solve the equation you first divide by 10 and then subtract 15.

Tom says that to solve the equation you first subtract 15 and then multiply by 10.
Tom says that to solve the equation you first subtract 15 and then multiply by 10.

Tom says that to solve the equation you first add 15 and then divide by 10.
Tom says that to solve the equation you first add 15 and then divide by 10.

Tom says that to solve the equation you first subtract 15 and then divide by 10.
Tom says that to solve the equation you first subtract 15 and then divide by 10.

Answer 1

The correct reason that justifies Tom's solution is: Tom says that to solve the equation you first subtract 15 and then divide by 10. This is because to isolate the variable x, you need to undo the operations being done to it in the equation. So, you first subtract 15 from both sides to get 10x = 5, and then divide by 10 to find x = 1/2.