You've got five different problems in this photo ... four on top and the word problem on the bottom ... and they're all exactly the same thing: Taking two points and finding the slope of the line that goes through them.
In every case, the procedure is the same.
If the two points are (x₁ , y₁) and (x₂ , y₂) , then
the slope of the line that goes through them is
Slope = (y₂ - y₁) / (x₂ - x₁) .
This is important, and you should memorize it.
#1). (8, 10) and (-7, 14)
Slope = (14 - 10) / (-7 - 8) = 4 / -15
#2). (-3, 1) and (-17, 2)
Slope = (2 - 1) / (-17 - -3) = (2 - 1) / (-17 + 3) = 1 / -14
#3). (-20, -4) and (-12, -10)
Slope = [ -10 - (-4) ] / [ -12 - (-20) ]
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The word problem:
This question only gives you one point on the graph,
and then it wants to know what's the slope ?
What are you going to do for another point ?
A "proportional relationship" always passes through the origin,
so another point on the line is (0, 0) .
Now you have two points on THAT line too, and you can easily
find its slope.
Answer:
- 10 liters of orange juice
- 5 liters of champagne
Step-by-step explanation:
Let c represent the number of liters of champagne Lauren uses. Then (15-c) will be the number of liters of orange juice. The total cost of the mix will be ...
12c +1.50(15-c) = 5.00(15)
10.5c = 52.50 . . . . . subtract 22.50, simplify
52.50/10.5 = c = 5 . . . . divide by the coefficient of c
Then the amount of orange juice is ...
15 -c = 15 -5 = 10 . . . . liters
Lauren should use 5 liters of champagne and 10 liters of orange juice.
Step-by-step explanation:
4) 24/30=4/5
5) 2/24=1/12
6)14/84=1/6
7) 20/45=4/9
8)7/49=1/7
