How do you solve abs(7-2x)=5?

2 Answers
Aug 26, 2017

x= 1 and 6

Explanation:

The use of the special brackets of | | means that whatever is inside them is considered as positive.

On the right side of the equals we have +5.

So the left side must end up as |+-5| giving:

|+-5|=+5

Ok!

Lets consider what will turn 7-2x into -5

Set color(white)("d")7-2x=-5

2x=7+5

x=12/2=+6

Check (color(white)(2/2)7-[2xx6]color(white)("d") ) -> 7-12 = -5 as required

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Lets consider what will turn 7-2x into +5

Set color(white)("d")7-2x=+5

2x=7-5

x=2/2=1

Check (color(white)(2/2)7-[2xx1]color(white)("d")) -> 5xx1=+5 as required

Aug 26, 2017

See a solution process below:

Explanation:

The absolute value function takes any term and transforms it to its non-negative form. Therefore, we must solve the term within the absolute value function for both its negative and positive equivalent.

Solution 1

7 - 2x = -5

-color(red)(7) + 7 - 2x = -color(red)(7) - 5

0 - 2x = -12

-2x = -12

(-2x)/color(red)(-2) = (-12)/color(red)(-2)

(color(red)(cancel(color(black)(-2)))x)/cancel(color(red)(-2)) = 6

x = 6

Solution 2

7 - 2x = 5

-color(red)(7) + 7 - 2x = -color(red)(7) + 5

0 - 2x = -2

-2x = -2

(-2x)/color(red)(-2) = (-2)/color(red)(-2)

(color(red)(cancel(color(black)(-2)))x)/cancel(color(red)(-2)) = 1

x = 1

The Solutions Are: x = 6 and x = 1