1.

а) 9+6+11 = 26

б) 5*18*4 = 360

в) 82+14+18 = 114

2.

Sкруга = πr²

Cкруга = 2πr

S = 8*8π = 64π

C = 2*8π = 16π

3.

а) 4x-9 = 19

4x = 28 | :4

x = 7

б) 8+(x-4) = 9

x + 4 = 9

x = 5

в) 6(x-5) = 30

6x - 30 = 30

6x = 60 | :6

x = 10

г) x+0.76 = 37

x = 37-0.76

x = 36.24