On these questions question 1: 1/4z+8=12 question 2: -3(2n+1)+7=-5 queston 3: 2.5(t-2)-6=9

1/4z + 8 = 12
1/4z = 12 - 8
1/4z = 4
z = 4 / (1/4)
z = 4 * 4/1
z = 16 <===

-3(2n + 1) + 7 = -5
-6n - 3 + 7 = -5
-6n + 4 = -5
-6n = -5 - 4
-6n = -9
n = -9/-6
n = 3/2 <===

2.5(t - 2) - 6 = 9
2.5t - 5 - 6 = 9
2.5t - 11 = 9
2.5t = 9 + 11
2.5t = 20
t = 20 / 2.5
t = 8 <===