Answer:
y = 7x + 20
Step-by-step explanation:
Look where the line meets y-axis. At that point, x = 0 and y = meeting point = 20
So, (x, y) = (0, 20) is a point on the line.
Now, find another point on the line. e.g., (x', y') = (10, 90) is one such point.
Equation of a line is y = mx + c
To find the slope, we do the following:
y = mx + c y' =mx' + c
c = y - mx c = y' - mx'
Equating equations for c gives
y - mx = y' - mx' => m (x' - x) = y' - y => m = (y' - y) / (x' - x)
So, the slope will be: m = (90 - 20) / (10 - 0) = 70/10
=> m = 7
Now, constant c can be calculated using c = y - mx
c = 20 - 7 x 0 => c = 20
<em>(You can cross-check value of c by putting x' and y' values in c = y' - mx' = 90 - 7 x 10 = 20)</em>
Hence, the equation of the line is y = 7x + 20
