can u show ur work
George 8 gallons of paint and 3 brushes for 40$
and Henry buys 6 gallons and 2 brushes 31$
they buy the gallons and brushes for the same prices
I need help with a math question... please help?
2008-06-18 4:12 pm
回答 (9)
2008-06-18 4:27 pm
✔ 最佳答案
g = gallon of paint priceb = brush price
8g + 3b = 40 (eq1)
6g + 2b = 31 (eq2)
Multiply eq1 by 2, and eq2 by -3:
16g + 6b = 80
-18g - 6b = -93
Add the equations together:
-2g = -13
Divide by -2:
g = $6.50
Substitute into eq1:
8g + 3b = 40
8(6.5) + 3b = 40
52 + 3b = 40
3b = -12
b = $-4.00
Check using eq2:
6g + 2b = 31
6(6.5) + 2(-4) = 31
39 - 8 = 31
31 = 31
It checks, but there seems to be a problem. The price of the brushes should not be (-). I've tried it a couple of ways and the answer remains the same.
g = $6.50
b = -$4.00
2008-06-18 11:24 pm
Let x be the price of a gallon and y be the price of a brush.
8x+3y=40
6x+2y=31
The solution is x=6.5 & y=-4
This equation has a solution, but the price of a brush is negative $4. You'll have to change the prices.
8x+3y=40
6x+2y=31
The solution is x=6.5 & y=-4
This equation has a solution, but the price of a brush is negative $4. You'll have to change the prices.
2008-06-18 11:22 pm
8p + 3b = 40
6p + 2b = 31
multiply 1st equation by 3, 2nd by 4, then subtract:
24p + 9b = 120
24p + 8b = 124
----------------------
......... 1b = -4
8p + 3b = 40
8p + 3(-4) = 40
8p = 52
p = 6.5
silly solution, brushes are free and they give you $4 to take one.
6p + 2b = 31
multiply 1st equation by 3, 2nd by 4, then subtract:
24p + 9b = 120
24p + 8b = 124
----------------------
......... 1b = -4
8p + 3b = 40
8p + 3(-4) = 40
8p = 52
p = 6.5
silly solution, brushes are free and they give you $4 to take one.
2008-06-18 11:20 pm
price of paint gallon = x, price of brush = y
8x+3y = 40
6x+2y = 31
8x = 40 - 3y
x = 5 - (3/8)y
30 - (18/8)y + (16/8)y = 31
30 -(2/8)y = 31
-2/8y = 1
y = -$4
x = $52/8
??
8x+3y = 40
6x+2y = 31
8x = 40 - 3y
x = 5 - (3/8)y
30 - (18/8)y + (16/8)y = 31
30 -(2/8)y = 31
-2/8y = 1
y = -$4
x = $52/8
??
2008-06-18 11:31 pm
x = the costs of each gallon of paint
y = the costs of each brush
8x + 3y = 40 (solve using elimination)
6x + 2y = 31
8x + 3y = 40
3(8x + 3y) = 3(40)
24x + 9y = 120
6x + 2y = 31
4(6x + 2y) = 4(31)
24x + 8y = 124
...24x + 9y = 120
-- 24x + 8y = 124
-------------------------
y = -4
(impossible answer, the costs won't be negative.)
y = the costs of each brush
8x + 3y = 40 (solve using elimination)
6x + 2y = 31
8x + 3y = 40
3(8x + 3y) = 3(40)
24x + 9y = 120
6x + 2y = 31
4(6x + 2y) = 4(31)
24x + 8y = 124
...24x + 9y = 120
-- 24x + 8y = 124
-------------------------
y = -4
(impossible answer, the costs won't be negative.)
2008-06-18 11:30 pm
8p + 3b = 40
6p +2b = 31
16p +6b = 80
18p +6b =93
2p = 13
p= 6.5
Yhis leads to no solution
6p +2b = 31
16p +6b = 80
18p +6b =93
2p = 13
p= 6.5
Yhis leads to no solution
2008-06-18 11:19 pm
so what is the question?
2008-06-18 11:17 pm
no
emmm george spent more money
good luck with math
xoxo
=/
emmm george spent more money
good luck with math
xoxo
=/
2008-06-18 11:17 pm
that is not a question thats a statement
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