Karla is given the equation 10x + 15 = 20 to solve. She says the solution is 1/2
.
Which reason justifies her solution?
Responses
A Karla says that to solve the equation you first add 15 and then multiply by 10.Karla says that to solve the equation you first add 15 and then multiply by 10.
B Karla says that to solve the equation you first multiply by 10 and then add 15.Karla says that to solve the equation you first multiply by 10 and then add 15.
C Karla says that to solve the equation you first subtract 15 and then divide by 10.Karla says that to solve the equation you first subtract 15 and then divide by 10.
D Karla says that to solve the equation you first divide by 10 and then subtract 15.
B Karla says that to solve the equation you first multiply by 10 and then add 15.
The correct reason that justifies Karla's solution is option D: Karla says that to solve the equation you first divide by 10 and then subtract 15.
The equation given is 10x + 15 = 20. To solve this equation, we need to isolate the variable, x.
To explain the process, let's go through the options one by one:
Option A: Karla says that to solve the equation you first add 15 and then multiply by 10.
This is not correct. In order to isolate the variable, we need to perform the inverse operations in reverse order. Adding 15 and then multiplying by 10 would not result in finding the value of x.
Option B: Karla says that to solve the equation you first multiply by 10 and then add 15.
This is correct. We need to start by subtracting 15 from both sides of the equation to get: 10x = 20 - 15 which simplifies to 10x = 5. Next, we divide both sides by 10 to isolate x: x = 5/10 which simplifies to x = 1/2.
Option C: Karla says that to solve the equation you first subtract 15 and then divide by 10.
This is not correct. We should start by subtracting 15 from both sides, but then we need to divide by 10, not subtract.
Option D: Karla says that to solve the equation you first divide by 10 and then subtract 15.
This is not correct. We should first subtract 15 from both sides and then divide by 10, not the other way around.
Based on the explanations above, the correct reason is option B:
Karla says that to solve the equation you first multiply by 10 and then add 15.