algebra hmwrk help..please?

Question

writing systems of linear equations
define variables then solve the system

1.)two groups of students order burritos and tacos at a local resturant. One order of 2 burritos and 4 toacos costs $11.33. the other order of 9 burritos and 5 tacos costs $23.56. Find the cost of a burrito and the cost of a taco.
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2.) Kendra owns a resturant. She charges $1.50 for 2 eggs and one peive of toast, and $.90 for one egg and one peice of toast. Write a system of equations to determine how much she charges for one egg and one peice of toast. Let x represent the number of eggs and y represent the number of toast.
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3.) You decide to market your own computer software. You must invest $3,255 for computer hardware ans spend $2,90 to buy and package each disk. If each program sells for $13.75, how many copies must you sell to break even?

Answer 1

2b+4t=11.33 *5
9b+5t=23.56 *-4

10b+20t=56.65
-36b-20t=-94.24
adding
-26b=-37.59
b=1.45
sub b=1.45 in 2b+4t=11.33
2.90+4t=11.33
4t=8.43
t=2.11

2.2e+1t=1.50
1e+1t=0.90
subtracting
1 egg=$0.60
substituting in 1e+1t=0.90
toast=$0.30

3.investment=3,255+2.90n
at break even investment=returns
returns=13.75n
equating
13.75n=2.90n+3255
10.85n=3255
n=3255/10.8
=300
to break even he should sell 300 copies

Answer 2

1) write two equations, with variables b and t for burrito and taco.
The first equation is:
2b + 4t = 11.33
The second is
9b + 5t = 23.56
You need to get rid of one of the variables. Multiply the first equation by 9 and the second by 2, and subtract one from the other. Here is some help:
18b + 36t = 9*11.33
Now, you can do the rest.
Multiply each term in the second equation by 2.

You can do the rest of this. I believe in you!

2) You have the varible names here, and all you are asked for is the system of equations.
Here is the first: 2x + y = 1.50
You can write the second - and then you'll have the answer.

3) To break even, the money you spend must be equal to the money you take in.
The money you spend is$3255 + N * 2.90
The money you take in is N * 13.75
So you have ONE equation and one unknown:
3255 + 2.9*N = 13.75*N

To solve this, simply subtract 2.9*N from both sides of the equation and then you're really close!

Answer 3

1. let the cost one burrito is x and the cost of one taco be "y" then the eqn. for the first group is
2x + 4y = $11.33
and in the same way eqn. for the sec. grp. is
9x + 5y = $ 23.56
now solve these eqns. for x and y and the value of x wil be the cost of burrito and value of y is the cost of taco

2.
if x is the no. of the eggs and y is the no. of toast then
then if she sale two eggs and one piece of toast for $ 1.5o then eqn. is
2x + y = $1.50
and for one piece of egg and one piece of toast she charge $ .90
then the eqn. is
x + y = $.90
now solve these two linear eqns. for x and y and the anw. will be there


3/. well i couldnt understand the last question properly. i think that some inform. is left.