Answer:

1. x + 7

2. 2x - 6

3. 12x - 8

4. 7x^2+6x

Step-by-step explanation:

1. If we are to calculate what zab's age would be 7 years from now. We would just add 7 to his age (x).

x + 7

2. Joan is twice as old as her sister. If x = her sisters age now and we are trying to find her age six years ago, we would multiply her sisters age by 2 and subtracting it from six years.

2x - 6

3. The formula for a perimeter of a sqaure is 4(s) where s = side.

Since side is equal to 3x - 2

4(3x - 2)

12x - 8

4. His income is 7x + 6 daily. So his total income in x days is:

x(7x + 6)

7x^2 + 6x