Try this solution:
Answer: 6 & 4.5 (m-per-h)
Step-by-step explanation:
- The basic formula used in this task is S=V*t, where S - distance, V - speed, t - time.
- the downstream speed is: V+Vc, where V - the speed of the boat in still water, Vc - the speed of the current.
- the upstream speed is: V-Vc.
- according to the described above the distance for downstream is S1=(V+Vc)*t1, where t1=10; the distance for upstream is S2=(V-Vc)*t2, where t2=70.
- for whole travel down- and upstream: S=S1+S2.
- Using these it is possible to make up the system of the equations:

V - the speed of the boat in still water - 6 miles per hour, Vc - the speed of the current - 4.5 miles per hour. All the details for the system of the equations are in the attachment.
Answer: x/2-y^3=1 & x^2+y=4
Step-by-step explanation:
Find the prime factorization of 54
54 = 2 × 3 × 3 × 3
Find the prime factorization of 99
99 = 3 × 3 × 11
To find the GCF, multiply all the prime factors common to both numbers:
Therefore, GCF = 3 × 3
GCF = 9
<h2>
1. Pascal’s triangle</h2>
Pascal's triangle is an strategy in math that stands for a triangular array we use to solve problems of binomial coefficients. This strategy is called after the mathematician Blase Pascal. It consists in number patters. So in this problem we need to solve this following Pascal’s triangle strategy:

The strategy consists in building a triangle. So 1 is the first and last numbers in each row of Pascal’s Triangle. Next, every other number in each row is formed when you add the two numbers directly above the number, as shown in Figure below. So:

<h2>
1. Binomial Expansion</h2>
A binomial is a polynomial having two terms. So binomial expansion is a method that stands for a formula that gives us a quick method of raising a binomial to a power. So, for n=3, the binomial expansion can be written as:
