Have any hard time with this question cannot figure out how

Solution

1)

The equation of line will be of the form

y = mx + C

x = 0 corresponds to the year 1990

y(0) = m(0) + C = C = 118.3

Since x=0 corresponds to year 1990, hence x=10 will correspond to year 2000

y(2000-1990) = m(10) + C = 158.3

10m + C = 158.3

10m = 40

m = 4

Hence the equation of line will be

y = 4x + 118.3

year 1996 corresponds to the value of x=6

y = 4(6) + 118.3 = 142.3

year 2002 corresponds to the value of x=12

y = 4(12) + 118.3 = 166.3

2)

The equation of line will be of the form

y = mx + C

x = 0 corresponds to the year 1990

y(0) = m(0) + C = C = 135.9

Since x=0 corresponds to year 1990, hence x=10 will correspond to year 2000

y(2000-1990) = m(10) + C = 155.9

10m + C = 155.9

10m = 20

m = 2

Hence the equation of line will be

y = 2x + 135.9

y(1994) = 2(4) + 135.9 = 143.9

y(2005) = 2(15) + 135.9 = 165.9