Answer:
So, the initial number of apples is 7.
Step-by-step explanation:
The number of apples of An, Binh, and Chi are the same. An gave away 17 apples, Chi gave away 19 apples, so now Chi's apples are 5 times higher than the total remaining apples of An and Binh. How many apples did each of you have at first? (Solve the above problem by equation or system of equations)
Let the initial numbers of apples is a.
An gave 17 apples
Chi gave 19 apples
So,
x - 19 = 5 (x - 17 + x)
x - 19 = 5 (2x - 17)
x - 19 = 10 x - 85
9 x = 66
x = 7
Answer:
Skiing costs $30 per hour and Boating costs $51 per hour.
Step-by-step explanation:
Let cost per hour of skiing be x and cost per hour of boating be y. Let's dissect the problem into 2 simultaneous equations.
<em><u>"John paid $222 for four hours of skiing and two hours boating":</u></em>

<em><u>"He paid $213 for two hours skiing and three hours boating":</u></em>

<em>Now, if we solve for x in the 2nd equation and plug it in the 1st equation, we will have the value for y</em>. Work shown below.

Hence, y = 51
<em>Now, substituting this y value into the 1st equation and solving for x will give us the value of x.</em>

Hence, skiing costs $30 per hour and boating costs $51 per hour.
Answer:
-5x^2-2x
Step-by-step explanation:
When distributing, you multiply the term outside the brackets to all the terms in brackets.
If the term outside the bracket is negative, then when distributing/opening the brackets, the signs of the terms changes.
So in this prob. -x would multiply to both +5x and +2
-x*5x+-x*2
∴-5x^2-2x