Answer:
Step-by-step explanation:
So what you need to do is take the two points (1, -5) and (3, -1) and subtract them. You take y of the second group and subtract y of the first group.
-1 - (-5) = 4
Now you do the first numbers in each group with the second set being the number you subtract from.
3 - 1 = 2
Now you do 
. Rise = 4 Run = 2
= 2
Now the second part is saying y = 3x + c with your first set of numbers being x and y.
x = 1
y = -5
-5 = 3(1) + c
-5 = 3 + c
Subtract 3 from -5
-8 = c
The final answer is:
y = 3x - 8
X= cost per pizza
y= cost per soda
1ST VISIT TO RESTAURANT
x + 2y= $15.95
2ND VISIT TO RESTAURANT
3x + 5y= $45.90
STEP 1
multiply equation from 1st visit by -3. Will be able to solve by elimination method in step 2.
-3(x + 2y)= -3(15.95)
multiply -3 by each term
(-3 * x) + (-3 * 2y)= (-3 * 15.95)
-3x - 6y= -47.85
STEP 2
add 2nd visit equation to new 1st
visit equation in step 1.
3x + 5y= 45.90
-3x - 6y= -47.85
x term will cancel out; solve for y
-y= -1.95
divide both sides by -1
y= $1.95 per soda
STEP 3
substitute y value in either original equation to solve for x
x + 2y= $15.95
x + (2 * 1.95)= 15.95
multiple in parentheses
x + 3.90= 15.95
subtract 3.90 from both sides
x= $12.05 per pizza
CHECK
3x + 5y= $45.90
3(12.05) + 5(1.95)= 45.90
36.15 + 9.75= 45.90
45.90= 45.90
ANSWER: Each pizza costs $12.05 and each soda costs $1.95.
Hope this helps! :)
Answer:
Between 19 and 55, inclusive
Step-by-step explanation:
70 < Average < 79 (inclusive)
4×70 < sum < 4×79 (inclusive)
280 < sum < 316
280 < 92 + 84 + 85 + X < 316
280 < 261 + X < 316
19 < x < 55
Fourth score can be between 19 and 55, inclusive
