Answer is t = 4d + 5
Explanation
We know the equation is in slope intercept form, y = mx + b
We are looking for “m” or slope and “b” y intercept
By looking at the graph, we can chose two sets of points and find slope
(1, 9) and (2,13)
Formula for slope is y2 - y1 over x2 - x1
13 - 9 over 2 - 1 = 4/1 or slope of 4
We can find y intercept or “b” using point slope formula y - y1 = m (x - x1)
y - 9 = 4 ( x - 1)
Multiply
y - 9 = 4x - 4
Add 9 to both sides to isolate y
y -9 +9 = 4x -4 + 9
Simplify
y = 4x + 5
Since x = d and y = t we change this solution to
t = 4d + 5