Answer:
declaration = - 0.55 m/s²
Step-by-step explanation:
The declaration is a negative accelaration.
Therefore:

a = ?
v = 70 of 15% = 10.5 km/h to m/s = 2.9 m/s
u = 70 km/h to m/s = 19.4 m/s
t = 30 seconds

a = - 0.55 m/s²
A slope intercept form: y = mx + b where m = slope and b = y -intercept
A slope of 3/2 is given
So y = 3/2 x + b
To find b:
b = y - mx
A line passes through the point (4, -6)
b = -6 - (3/2)(4)
b = -6 - 6
b = - 12
Answer
Equation in slope intercept form: y = 3/2 x - 12
I can not see the image sorry!!!