# Hello! Please, tell me which method solving this equation (17 = 10 -x + 2) is correct:a)    17 = 10 -x +2    17 = 12 -x / -12    5 = -x /: -1   -5 = xb)   17 = 10 -x +2 /-2   15 = 8 -x...

Hello!

Please, tell me which method solving this equation (17 = 10 -x + 2) is correct:

a)
17 = 10 -x +2
17 = 12 -x / -12
5 = -x /: -1
-5 = x

b)
17 = 10 -x +2 /-2
15 = 8 -x /-8
7 = -x /:-1
-7 = x

Alexander.

gsenviro | Certified Educator

Option A is correct.

17 = 10-x+2 = 12-x

or, x = 12-17 = -5.

An easy way to figure out the right approach is to substitute the answer into the original equation and verify if it satisfies the equation.

If approach A is correct, then x = -5 should satisfy the equation,

i.e. 17 = 10-(-5)+2 = 10 +5+2 = 17.

since LHS = RHS, therefore x=-5 is an answer.

If option B were correct, then x = -7 should satisfy the equation

i.e., 17 = 10-(-7)+2 = 10+7+2 = 19.

here LHS is not equal to RHS, thus x=-7 is not a solution. Hence approach B does not work.

Therefore, option A is correct and provides the right answer.

Hope it helps.

bababeta | Certified Educator

This question requires algebra. To simplify this equation, you first need to add 2 and 10. This means that 17 equals to 12 -x. Next you need to take 12 on the left hand side and subtract it from 17 as side change means sign change. Now 5 equals to -x and x will be equal to 5. This shows that option A is correct.

17=10-x+2

17=10+2 -x

17= 12 -x

17-12= -x

5= -x

x =-5

Hope it helps!

Nolan McShea | Student

a) Is correct.

Instead of looking at how both of these choices work, you can instead just do the algebra yourself to see which one of the answers has the value of x that you solved for. So, doing the algebra,

[See attached image for full explanation]

Hope I helped!

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kspcr111 | Student

17=10-x+2

=> 17=12-x

=> 17-12= -x

=> 5= -x

=> x =-5