Elimination:
7x - 3y = 20
5x + 3y = 16
(add)
12x = 36
÷ 12
x = 3
(5 × 3) + 3y = 16
15 + 3y = 16
- 15
3y = 1
÷ 3
y = 1/3
Substitution:
5x + 3y = 16
- 3y
5x = 16 - 3y
÷ 5
x = 3.2 - 0.6y
5(3.2 - 0.6y) + 3y = 16
16 - 3y + 3y = 16
16 = 16
- 16
6y = 0
÷ 6
y = 0
Sorry the substitution messed up for some reason, I'll fix it after I've answered the other question
Answer:
both are -10
Step-by-step explanation:
#1
x1 y1 x2 y2
1.5 180 6 135
(Y2-Y1) (135)-(180)= -45 ΔY -45
(X2-X1) (6)-(1.5)= 4.5 ΔX 4.5
slope= -10
B= 195
Y =-10X +195
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#2
x1 y1 x2 y2
1 175 8 105
(Y2-Y1) (105)-(175)= -70 ΔY -70
(X2-X1) (8)-(1)= 7 ΔX 7
slope= -10
B= 185
Y =-10X +185
The correct answer is y2+20y+200
Answer:
The answer is that both plans are equal.
Step-by-step explanation:
you start by putting the plans into an equation then you set them equal to each other. you need to assign a variable for the number of months. we'll call it M. It would look like this:
plan A - 25 + 8M
plan B - 5 + 12M
25 + 8M = 5 + 12M
Then you solve which looks like this:
25 + 8M = 5 + 12M
-8M -8M
25 = 5 + 4M
-5 -5
20 = 4M
/4 /4
5 = M
Now we aren't done after finding out what M equals. We still need to know what each plan will cost. So, we substitute what M equals into the equation. if they both end up equaling the same thing then its equal. if you get two different numbers they aren't. it would look like this:
25 + 8(5) = 5 + 12(5)
25 + 40 = 5 + 60
65 = 65
They are equal. Both plans will cost 65 dollars.
