a, `x -5/6=11/13`
`=> x = 11/13+5/6`
`=> x = 66/78+65/78`
`=> x = 131/78`
b) `15/16 - x = 1/12 + 2/5`
`=> 15/16-x = 5/60+24/60=29/60`
`=> x=15/16-29/60`
`=> x=225/240 - 116/240`
`=> x = 109/240`
c)` 7/8 + 8/9 = x - 1/2`
`=> x-1/2 = 63/72+64/72`
`=> x-1/2=127/72`
`=> x=127/72+36/72`
`=> x=163/72`
d) `13/12 - 5/7 = x - 6/7`
`=> x = 13/12-5/7+6/7`
`=> x=13/12+1/7`
`=> x=91/84+12/84`
`=> x=103/84`
e, ` x - 1/2 = 16/7 - x `
`=> 2x=16/7+1/2`
`=> 2x= 32/14+7/14`
`=> 2x=39/14`
`=> x=39/28`