how do i solve?

Basically, you solve as follows:
x/7 - 1/2 = 1 - 2x/5
Step 1:
You need to find a common denominator (ie. a number which is a multiple of 2, 5 and 7). The lowest one would be 70.
You then multiply the whole formula by 70:
70x/7 - 70/2 = 70 - 140x/5
Now cancel out the denominators by simplifying the fractions:
10x - 35 = 70 - 28x
Now solve for x:
38x = 105
x = 105/38 = 2 29/38

105/38
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x/7 - 1/2 = 1 - 2x/5
x/7 + 2x/5 = 1 + 1/2
5x/35 + 14x/35 = 2/2 + 1/2
19x/35 = 3/2
38x = 105
x = 105/38

x/7 - 1/2 = 1 - 2x/5
x/7 + 2x/5 = 1 + 1/2
70(x/7 + 2x/5) = 70(1 + 1/2)
10x + 28x = 70 + 35
38x = 105
x = 105/38

x/7+2x/5=1.5
(5x+14x)/35=1.5
19x=1.5X35
x=2.763

This is a linear eqn. in 1 variable. Solving equations can't get easier than this !

x/7 + 2x/5 = 1 + 1/2 = 3/2
The LCM betn 5 and 7 is 35.
(5x + 14x)/35 = 3/2
19x = 105/2
=> x = 105/38 = 2.763

2x-7/14 = 5-2x/5

(2x-7)*5 = (5-2x)*14

10x-35 = 70-28x

10x+28x = 70+35

38x= 105

x= 105/38

10x - 35 = 70 - 28x
38x = 105
x = 105 / 38

If you mean:-
x/7 - 1/2 = (1 - 2x) / 5
10x - 35 = 14(1 - 2x)
10x - 35 = 14 - 28x
38x = 49
x = 49/38

x/7 + 2x/5 = 1 + 1/2
19x/35 = 3/2
x = 3/2 * 35/19
x = 70/38

http://reference.wolfram.com/mathematica/ref/Solve.html
www.wolfram.com
www.ocw.MIT.edu/Mathematics-at-MIT

if i told you it would defeat the purpose, but put all the x's on one side and the rest of the other and then get rid of the fractions by multiplication. You can then find the answer through division. Don't be afraid of asking your teacher.