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7x-(-1)/-8=-4

7x-(1)/8=-4

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Ginger M. | Mathematics by Ginger (intermediate, secondary)Mathematics by Ginger (intermediate, sec...
4.9 4.9 (77 lesson ratings) (77)
0
Be careful about using parenthesis to indicate whether it's:
7x - 1/8 = -4
or
(7x + 1)/-8 = -4
 
these yield two different answers. 
 
 
Kristina K. | A Tutor With Skills, Experience, Knowledge & PatienceA Tutor With Skills, Experience, Knowled...
4.8 4.8 (45 lesson ratings) (45)
0
[(7x)-(-1)]/-8=
(7x+1)/-8=-4
7x+1=32 ... Cross multiplication
     -1   -1
(7x)/7=31/7
x=31/7
 
You can check this value for x by plugging it into the original equation
[7*(31/7)-(-1)]/-8
(31+1)/-8
32/-8=-4
-4=-4
 
Kim Z. | Math Tutor and CoachMath Tutor and Coach
5.0 5.0 (3 lesson ratings) (3)
0
7x - 1/8  = -4
 
get rid of the fraction by multiplying each term by 8:
 
56x - 1 = -32
 
add 1 to both sides to get:
 
56x = -31
 
divide both sides by 56 to get:
 
x = -31/56
 
Your Answer is, x = -31/56