Answer:
4 hours
Step-by-step explanation:
The general formula for distance, rate and time is:
d = rt, where distance is the product of rate multiplied by time
Given that one train is moving at a rate of 70 mph and one is moving at a rate of 62 mph in the opposite direction, the combined distance over time is equal to 528 miles. Using the variable 't' for time:
70t + 62t = 528
Combine like terms: 132t = 528
Divide both sides by 132: 132t/132 = 528/132 or t = 4 hours
Multiply the bracket by 5
I used PEMDAS
P= parenthesis
E= exponents
M=multiplication
D= division
A= addition
S= subtraction
7r+2= 5(r-4)
7r+2= 5r-20
Move 5r to the left hand side . Positive 5r changes to negative 5r
7r-5r+2= 5r-5r-20
2r+2=- 20
2r+2-2= -20-2
Move positive 2 to the right hand side. Changes to negative -2
2r+2-2= -20-2
2r= -22
Divide by 2 for 2r and -22
2r/2= -22/2
r= -11
Answer is r= -11
<span>2x+y=400
A=xy area of farmland
y=400-2x
A=400x-2x^2
A'(x)= 400 -4x derivative of area with respect to x
0=400-4x find out where f ' equals 0
4x=400
x=100
A'(x)= 400 -4x
A''(x)= -4 check 2nd derivative. if negative then relative max at x=100
2x+y=400
y=200
dimensions 100x200
hope it helped</span>
C my friend had this test, if im wrong im super sorry.
