Don’t forget to scroll down to see the new extra credit opportunity (Choosing Substitution or Elimination)!
Tonight’s homework was from 7.4 Practice B, #13-15 and #20. In case you forgot the paper, here are the problems:
#13: Solve using elimination.
4x – 3y = 16
16x + 10y = 240
#14: Solve using elimination.
20x + 10y = 100
-5x + 4y = 53
#15: Solve using elimination.
3x – 10y = -25
5x – 20y = -55
#20 Travel Agency A travel agency offers two Chicago outings. Plan A includes hotel accommodations for three nights and two pairs of baseball tickets worth a total of $557. Plan B includes hotel accommodations for five nights and four pairs of baseball tickets worth a total of $974. Let x represent the cost in dollars of one night’s hotel accommodations and let y represent the cost in dollars of one pair of baseball tickets.
(a) Write a linear system you could use to find the cost of one night’s hotel accommodations and the cost of one pair of baseball tickets.
(b) Solve the linear system to find the cost of one night’s hotel accommodations and the cost of one pair of baseball tickets.
Check in comments section for hints, and leave a comment if you have a question. Don’t forget to tell me what you’ve tried so far, just like Emma did for “Homework 4/14″. Good luck!
#1) 4x – 3y = 16 4x-3*8=16
16x + 10y = 240 4x-24=16
4x= 40
-16x+12y=-64 x=10
16x+10y=240
16x cancels out the solution o this system is (10,8)
12y=-64
10y=240
22y=176
y=8
#2) 20x + 10y = 100
-5x + 4y = 53
20x+10y=100
-20x-16y=-212
20x cancels out
10y=100
-16y=-212
-6y=-112
ms krishnan i got confused on this one i kinda got lost on wat i was doing so ill ask u tomorrow how to do it k but atleast i tried it
#3) 3x – 10y = -25 3*5-10y=-25
5x – 20y = -55 15-10y=-25
-10y=-10
-6x+20y=50 y=1
5x-20y=-55
the 20’s cancel out the solution to his system is (5,1)
-6x=50
5x=-55
-1x=-5
x=5