Answer:
9d = the cost of the tennisballs
Step-by-step explanation:
Answer:
<em>(a) x=2, y=-1</em>
<em>(b) x=2, y=2</em>
<em>(c)</em> 
<em>(d) x=-2, y=-7</em>
Step-by-step explanation:
<u>Cramer's Rule</u>
It's a predetermined sequence of steps to solve a system of equations. It's a preferred technique to be implemented in automatic digital solutions because it's easy to structure and generalize.
It uses the concept of determinants, as explained below. Suppose we have a 2x2 system of equations like:

We call the determinant of the system

We also define:

And

The solution for x and y is


(a) The system to solve is

Calculating:





The solution is x=2, y=-1
(b) The system to solve is

Calculating:





The solution is x=2, y=2
(c) The system to solve is

Calculating:





The solution is

(d) The system to solve is

Calculating:





The solution is x=-2, y=-7
The speed of one car is 'S'. The speed of the other car is (S + 10).
In 5 hours, the first car travels (5S) miles, and the other car travels 5(S + 10) miles.
Since they're going in opposite directions, the distance between them at any time
is the sum of the distance that each one has traveled.
500 = (5S) + 5(S + 10)
500 = 5S + 5S + 50
500 = 10S + 50
Subtract 50 from each side:
450 = 10S
Divide each side by 10
S = <u>45</u>
S + 10 = <u>55</u>
Use distributie property which is
a(b+c)=ab+ac
therefor
6x(x-4)=6x^2-24x
distribute the negative 1 infroont of the (9x-1)
-1(9x-1)=-9x+1
now we have
6x^2-24x-16x^2-9x+1
gropu like terms
6x^2-16x^2-24x-9x+1
add like terms
-10x^2-33x+1 is simplest form