How do you solve #abs(9+7x)=30#?

1 Answer
smendyka
Apr 30, 2017

See the entire solution process below:

Explanation:

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

Solution 1)

#9 + 7x = -30#

#-color(red)(9) + 9 + 7x = -color(red)(9) - 30#

#0 + 7x = -39#

#7x = -39#

#(7x)/color(red)(7) = -39/color(red)(7)#

#(color(red)(cancel(color(black)(7)))x)/cancel(color(red)(7)) = -39/7#

#x = -39/7#

Solution 2)

#9 + 7x = 30#

#-color(red)(9) + 9 + 7x = -color(red)(9) + 30#

#0 + 7x = 21#

#7x = 21#

#(7x)/color(red)(7) = 21/color(red)(7)#

#(color(red)(cancel(color(black)(7)))x)/cancel(color(red)(7)) = 3#

#x = 3#

The solution is: #x = -39/7# and #x = 3#

Related questions
See all questions in Absolute Value Equations
Impact of this question
2018 views around the world
You can reuse this answer
Creative Commons License