Đáp án:
c) `x/5 = -12/10`
`=> 10.x = -12.5`
`=> 10x = -60`
`=> x = -60/10`
`=> x =-6`
d) `-5/-2 = 10/-y`
`=>5/2 = 10/-y`
`=> -5.y = 10 .2`
`=> -5y =20`
`=> y = `-20/5`
`=> y = -4`
e) `-28/4 ≤ x < -21/7`
`=> -7 ≤ x < -3`
`=> x={ -7; -6; -5; -4}`
f) `-4/8 = x/-10 = -7/y = 2/-24`
`=> -1/2 = x/ -10 = -7/y = 1/-12`
`=> 2x = -1.-10 = y =-7.-12`
`=> 2x =10 =y =84`
`=> x= 10/2 = y =84`
`=> x= 5 = y =84`
vậy `x = 5; y= 84`
mong ctlhn ạ~~
