Math HomeWork? It is word problem solving, using substition or elimination!?

Question

You can choose either or, I have tried and can't figure it out, Sry Mrs. Stryker if you see this, i really did try it , and can't figure it out?!?!

This is a link to the picture if the html code did not work! Easy Best Answer!!!

http://i159.photobucket.com/albums/t159/pieloverllamas/mathhomework001-1.jpg

Answer 1

half the problem is getting the junk from the words into linear form

and then you get to solve it - so lets try books

$6.95X + $19.95Y = $60.75

and

2X + 4Y = 14

all we have to do is isolate X or Y and then substitute into the other equation

in the 2nd one a 2 is a variable of all soooooooo divide by two

x + 2y = 7

x= 7 - 2y

now that we 'know' what X =

we can sub into the other one

$6.95X + $19.95Y = $60.75

$6.95(7-2y) + $19.95y = 60.75

48.65 - 13.90y + 19.95y = 60.75

48.65 +6.05y = 60.75

6.05y = 12.10

y=2

go back and sub into your first equation we tore up

2X + 4Y = 14

2x + 4(2) = 14

2x + 8 = 14

and you got it from here

all the best

Answer 2

6)  Let x = paperback books and y = hardcover books

6.95x + 19.95y = 60.75

2x + 4y = 14

I would use substitution for this one because of all the decimals.

2x + 4y = 14

2x = -4y + 14

x = -2y + 7

Now, substitute what you know about x into the other equation and solve for y.

6.95(-2y +7) +19.95y = 60.75 (distrubute)

-13.90y + 48.65 + 19.95y = 60.75 (combine like terms)

6.05y + 48.65 = 60.75 (subtract to both sides)

6.05y = 12.10 (divide to both sides)

y = 2

To find x, you must plug the y that you just found into the equation that you used for substitution (you must you that equation, unlike the elimination method where you can use either of the equations ).

x = -2y +7

x = -2(2) + 7

x = -4 + 7

x = 3

So, you bought 3 paperback books and 2 hardcover books.

Now try the rest on your own =)

Answer 3

6.

x = 2 point books

y = 4 point books

6.95x + 19.95y = 60.75

2x + 4y = 14

x = 7 - 2y (I solved for x using the second equation)

6.95(7-2y) + 19.95y = 60.75

48.65 - 13.9y + 19.95y = 60.75

6.05y = 12.1

y = 2

Plug y back into both formulas

6.95x + 19.95(2) = 60.75

6.95x + 39.90 = 60.75

6.95x = 20.85

x = 3

2(3) + 4(2) = 14

6 + 8 = 14

You can try to figure the rest.