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


Thanks in advance,

Alexander.

Asked on by deeveetoo

6 Answers | Add Yours

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gsenviro | College Teacher | (Level 1) Educator Emeritus

Posted on

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.

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bababeta | Middle School Teacher | (Level 1) Adjunct Educator

Posted on

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! 

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Nolan McShea | Student, Grade 11 | (Level 2) Honors

Posted on

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 | In Training Educator

Posted on

17=10-x+2

=> 17=12-x

=> 17-12= -x

=> 5= -x

=> x =-5

So,option a is the answer

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glendadh | eNotes Newbie

Posted on

Option A is the correct option.

you can check this by substituting -5 back into the original equation

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