(4 marks) 5. solve the following equations: a) x+5 = 7 b) 2x - 8 = 20 c) 4x - 6x = 200 d) x+1= 5 3

a) x + 5 = 7

x + 5 - 5 = 7 - 5 (Subtract 5 from both sides)

x = 2

b) 2x - 8 = 20

2x - 8 + 8 = 20 + 8 (Add 8 to each side)

2x = 28

2x/2 = 28/2 (Divide each side by 2)

x = 14

c) 4x - 6x = 200

-2x = 200

-2x/-2 = 200/-2 (Divide each side by -2)

x = -100 (Note that a negative number divided by a negative number is positive, whereas a positive number divided by a negative number is negative)

d) x + 1 = 5

x + 1 - 1 = 5 - 1 (Subtract 1 from each side)

x = 4

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.