3^x + 3^2 = 90
Simplify the known power:
3^x + 9 = 90
Subtract 9 from both sides:
3^x = 81
Take the cubic root of both sides:
X = 4
The commutative property of multiplication.
B it is linear Bc it increases constantly. There is a constant slope that doesn’t change
S=d/t ⇒d=s*t
s=speed
d=distance
t=time
The first train :
d=x
x=70 miles/h*t ⇒ x=70t (1)
The second train
d=360 miles - x
360 miles - x=80 miles/h*t ⇒360-x=80t ⇒ x=360-80t (2)
therefore, with the equations (1) and (2) we have a systeme of equations:
x=70t
x=360-80t
we can solve this system of equations by equalization method.
70t=360-80t
70t+80t=360
150t=360
t=360/150=2.4 (≈2 hour 24 minutes)
Answer: the first train meet with the second train in 2 hour 24 minutes.
