Question

What is the value of a in the following equation: -a = 3a + 8?

A) 2
B) 4
C) -2
D) -4

Answer 1

The correct answer is: [C]: "-2 " .
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→ " a = - 2 " .
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Step-by-step explanation:
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Given: " -1a = 3a + 8 " ; Solve for "a" .

Add "1a" to each side of the equation:

→ " -1a + 1a = 3a + 1a + 8 ;

to get: 0 = 4a + 8 ;

↔ 4a + 8 = 0 ;

Subtract "8" from each side of the equation:

→ 4a + 8 − 8 = 0 − 8 ;

to get:

→ 4a = - 8 ;

Divide each side of the equation by "4" ;
to isolate "a" on one side of the equation; & to solve for "a" ;

→ 4a / 4 = -8 / 4 ;

to get:

→ a = -2 .
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The answer is: " a = -2 " .
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Answer 2

`-a = 3a + 8`

Add
`-3a` to both sides


`-4a = 8`

Divide both sides by
`-4`


`a = -2`

Choice C.

Check:


`3a + 8 = 3(-2) + 8 = 2 = -a \quad \checkmark`