Answer:
There are two possibilities:
and 
and 
Step-by-step explanation:
Mathematically speaking, the statement is equivalent to this 2-variable non-linear system:
First, 
is cleared in the first equation:
Now, the variable is substituted in the second one:
And some algebra is done in order to simplify the expression:
Roots are found by means of the General Equation for Second-Order Polynomials:
and 
There are two different values for :
There are two possibilities:
and
and
Answer:
50 of D and 10 of C
Step-by-step explanation:
First of all, put this data into 2 equations.
You sold 60 items, so C+D=60
C is $5 so we can represent it by 5C
D is $7 so we can represent it by 7D
You made $400 total from C and D, so 5C+7D=400
We can use simultaneous equations to solve this.
To eliminate one of these variables, we'll multiply the first one by 5 to make it 5C like the other.
5(C+D=60) (make sure you multiply both sides.)
so 5C+5D=300
5C+7D=400
Now we solve it:
5C-5C+7D-5D=400-300
7D-5D=100
2D=100
D=50
Now we can substitute this with one of the equations to find C
C+50=60
C=60-50
C=10
so, (10x5)+(50x7)=400
The equation must be 4x + y = 17
I will use the y-intercept slope version
y = - 4x + 17
Then the slope is negative (-4) and the y-intercept is 17.
The line passes through the points (0,17) and (0,17/4). The negative slope indicates that the line goes down from left to right (y decreases when x increases).
