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An absolute value equation I'm having a problem with

User Samudra
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3.9k points

1 Answer

2 votes

We need to solve the equation:

|8x + 5| = 29

In order to do so, we need to consider two cases:

0. When ,8x + 5 ≥ 0.

,

1. When ,8x + 5 < 0.

For the first case, the quantity inside the symbol | ... | is already non-negative. So, its absolute, which turns the expression into a non-negative one, won't do any changes:

0. When ,8x + 5 ≥ 0:

|8x + 5| = 8x + 5

|8x + 5| = 29

8x + 5 = 29

8x + 5 - 5 = 29 - 5

8x = 24

8x/8 = 24/8

x = 3

Now, for the second case, the quantity inside the symbol | ... | is negative. So, the symbol | ... | will change the sign of the expression inside it in order to make it non-negative:

0. When ,8x + 5 < 0:

|8x + 5| = -(8x + 5)

|8x + 5| = 29

-(8x + 5) = 29

-(8x + 5) * (-1) = 29 * (-1)

8x + 5 = -29

8x + 5 - 5 = -29 - 5

8x = -34

8x/8 = -34/8

x = -4.25

Therefore, the solution is {-4.25, 3}.

User Dor Shinar
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3.2k points