Respuesta :

#1

x-7>10

x>10 + 7 

x>17

#2

3x <= 21

x <= 21/3

x<= 7

#3

5a - 2<18

5a < 18 + 2

5a <20

a <20/5

a<4

#4

2t + 8 >= -4(t +1)

2t +8>= -4t -4

2t + 4t >= -4 - 8

6t >= -12

t>= -12/6

t>= -2