SOLUTION: im nt sure how to answer this question its: solve abs(-3x+7)=9 i did 7-9=2, so -3x=2 x=.66 but this doesnt seem right to me could you help me please?

Algebra ->  Rational-functions -> SOLUTION: im nt sure how to answer this question its: solve abs(-3x+7)=9 i did 7-9=2, so -3x=2 x=.66 but this doesnt seem right to me could you help me please?      Log On


   

Question 514801: im nt sure how to answer this question its: solve abs(-3x+7)=9
i did 7-9=2, so -3x=2 x=.66 but this doesnt seem right to me could you help me please?
Found 2 solutions by jim_thompson5910, oberobic:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
abs%28-3x%2B7%29=9 Start with the given equation


Break up the absolute value (remember, if you have abs%28x%29=a, then x=-a or x=a)

-3x%2B7=-9 or -3x%2B7=9 Set the expression -3x%2B7 equal to the original value 9 and it's opposite -9




Now lets focus on the first equation -3x%2B7=-9


-3x=-9-7Subtract 7 from both sides


-3x=-16 Combine like terms on the right side


x=%28-16%29%2F%28-3%29 Divide both sides by -3 to isolate x



x=16%2F3 Reduce






Now lets focus on the second equation -3x%2B7=9



-3x=9-7Subtract 7 from both sides


-3x=2 Combine like terms on the right side


x=%282%29%2F%28-3%29 Divide both sides by -3 to isolate x



x=-2%2F3 Reduce





So the solutions to abs%28-3x%2B7%29=9 are:

x=16%2F3 or x=-2%2F3

Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
Since you're using the absolute value function, you need to solve:
-3x+7 = 9
and
-3x+7 = -9
.
-3x + 7 = 9
-3x = 2
x = -2/3
.
-3x +7 = -9
-3x = -16
x = 16/3
.
check to ensure both answers are correct.
.
-3(-2/3) + 7 = ??
+6/3 +7 = 2 + 7 = 9
correct
.
-3(16/3) + 7 = ??
-48/3 + 7 = -16 + 7 = -9
correct
.
Answer: x = -2/3 or 16/3
.
Done.