3x +3y =20

[swimbad]

i have a simitanious equation 4x+2y=26 3x+3y=20. Is there a solution or is it a misprint????

 

[stapel]

Is what a misprint? The system of equations, or the solution in the back of the book?

Thank you.

Eliz.

 

[ting]

There's a bunch of ways.

Here's one.


4x+2y=26 [1]


3x+3y=20 [2]


Divide equation [1] by 2


2x + y = 13 [3]

Now multiply [3] by 3

6x + 3y = 39 [4]


Subtract [2] from [4]


6x + 3y = 39

3x + 3y=20


3x = 19

x = 19/3

Substitute into 2 and solve for y.


19 + 3y = 20

3y = 1


y = 1/3

 

[soroban]

Hello, swimbad!

(1) 4x + 2y = 26
(2) 3x + 3y = 20
Is there a solution or is it a misprint????

Sorry, but why wouldn't there be a solution?

Divide (1) by 2: . 2x + y .= .13
Divide (2) by 3: . . x + y .= .20/3

Subtract: .x .= .13 - 20/3 .= .19/3 . . . . .Then: .y .= .1/3

 

[Denis]

Is this an acceptable shortcut:

4x+2y=26 [1]
3x+3y=20 [2]
change [2] to:
4x + 3y = 20 + x
subtract [1] from that:
y = x - 6