Answer
a) slope: the average increase in the temperature of the surface per year
T-intercept: the average surface temperature in 1950
b) $17^{\circ}~C$
Work Step by Step
a) The slope represents the average increase in the temperature of the surface per year ($0.02^{\circ}~C/year)$, whilst the T-intercept represents the average surface temperature in 1950 ($15^{\circ}~C)$.
b) We have the time period of:
$t=2050-1950=100$
Thus
$T(100)=0.02(100)+15=17^{\circ}~C$
