19&20 bantuu mohonnnnnnnnnnn

19.
[tex](39 \times 4) - (6 \times 0) - (5 \times ( - 1)) \\ = 156- (0 + ( - 5) \\ = 156- 5 = 151[/tex]
20.
[tex]k = (2 \times 4x) + (2 \times 2x) \\ 120 = 8x + 4x \\ 12x = 120 \\ x = 120 \div 20 = 10m[/tex]