Set 7x-4 and 31 equal to each other
7X-4=31
Add four to both sides
7X=27
X=3
The answer is D
Answer:
{x,y} = {3/7,-43/7}
Step-by-step explanation:
System of Linear Equations entered :
[1] x + 3y = -18
[2] -x + 4y = -25
Graphic Representation of the Equations :
3y + x = -18 4y - x = -25
Solve by Substitution :
// Solve equation [1] for the variable x
[1] x = -3y - 18
// Plug this in for variable x in equation [2]
[2] -(-3y-18) + 4y = -25
[2] 7y = -43
// Solve equation [2] for the variable y
[2] 7y = - 43
[2] y = - 43/7
// By now we know this much :
x = -3y-18
y = -43/7
// Use the y value to solve for x
x = -3(-43/7)-18 = 3/7
Solution :
{x,y} = {3/7,-43/7}
Answer:
C = 100p + 200
Step-by-step explanation:
Because C is the total cost per day, 200 is the y-intercept because it's paid daily.
The 100 is the slope since "he pays a cost of $100 per phone produced)".
y = -9
Ok so to write the equation of the line you will need the slope and y-intercept. Since we are given two-point we can easily find the slope by using this equation for slope formula:

So now that we have our equation we can just plug in the numbers:

After subtracting you should get:
0/8
Since zero is in the numerator and you can't divide zero by anything, the slope is 0. We still need the y-intercept for the equation however since the slope is 0 there is no need to put anything else.
Then to find the y-intercept all you have to do is plug in one of the coordinatines into the slope equation to solve, for example, using the point (5,-9):

B is the variable for the y-intercept. Also notice how I put 0 as our slope into the equation. Now all you have to do is solve for b. Which you would get b = -9. Since you have your slope and your y-intercept now you just write out your equatoin for the line which is:
y = 0x - 9
**Just write it as
y = -9