Step-by-step explanation:
eqn of line : y = mx+ c
m = slope or gradient
c = y-intercept.
Lets take (1,6) = (x1,y1) and (2,3) = (x2,y2)

Substitute x = 1 and y = 6 into equation,

Therefore substituting m and c value, equation of line is

-3(6-10v-5v)
=-3(6-15v)
=-18+45v
-18+45v is the final answer.
21, cause if sarah had twice as mych she would have 42 and 42+21=63