84)
a) x + 7 = 11
x = 11 - 7
x = 4
b) 5 + x = 22
x = 22 - 5
x = 17
c) x - 8 = 5
x = 5 + 8
x = 13
d) 38 - x = 32
38 - 32 = x
6 = x
x = 6
e) 9x = 36
x = 36 / 9
x = (9 * 4) / 9
x = 4
f) 100x = 3
x = 3 / 100
x = 0,03
g) x / 4 = 3
x = 3 * 4
x = 12
h) 30 / x = 5
30 / 5 = x
(6 * 5) / 5 = x
6 = x
x = 6
i) x / 15 = 10 / 3
x = (15 * 10) / 3
x = (3 * 5 * 10) / 3
x = 50
85)
a) t + 5 = 12
t = 12 - 5
t = 7
b) t - 4 = 20
t = 20 + 4
t = 24
c) 14 + t = 10
t = 10 - 14
t = (-4)
d) 40 - t = 8
40 - 8 = t
t = 32
e) 4t = 24
t = 24 / 4
t = 6
f) t / 2 = 8
t = 8 * 2
t = 16
g) 3t = 2
t = 2 / 3
h) 2 / 3 + t = 10 / 3
t = 10 / 3 - 2 / 3
t = 8 / 3
i) t - 3/4 = 5/4
t = 5/4 + 3/4
t = 8/4
t = 2
86)
a) x + 10 = (-3)
x = -3 - 10
x = (-13)
b) 12 = 3 + x
x = 12 - 3
x = 9
c) -x + 5 = 15
x = 5 - 15
x = (-10)
d) 5x = 24
x = 24 / 5
e) -12 = 2x
x = (-12) / 2
x = (-6)
f) x / 5 = 4
x = 4 * 5
x = 20
