Answer:
x= 7.5 mile/h
y= 3.5 miles / h
Step-by-step explanation:
Given x and y
so, x+y = speed down river
and x-y= speed up river
using
travel time = distance / speed for each case;
we get;
22/x+y=2 ---(1)
and
22/x-y=5.5 -----(2)
Solving equations simultaneously
eq 1 gives
2x+2y=22 ---(3)
eq 2 gives
5.5x-5.5y=22 ----(4)
Multiply eq 3 by 2.75
==> 5.5x+5.5y=60.5 --- (5)
adding eq 4 with eq 5
==> 11x =82.5
==> x= 7.5 miles/h
put this value in eq 3
==> 2(7.5)+2y=22
==> 2y=22-19.8
==> 2y=7
==> y = 3.5
You have sold 72, and your friend has sold 74. Meaning your friend has sold 2 more magazine subscriptions than you.
Answer: Yes, it means 3 times the square root of 2. First, find the square root of 2. Then multiply that value by 3. You can also type it into a calculator, and it will give you the exact value.
The derivative of f(x) at x=3 is 2x=6 approaching from the left side (apply power rule to y=x^2). The derivative of f(x) at x=3 is m approaching from the right side. In order for the function to be differentiable, the limit of derivative at x=3 must be the same approaching from both sides, so m=6. Then, x^2=mx+b at x=3, plug in m=6, 9=18+b, so b=-9.
