Question

Use Cramer's rule to find the number of items the company must sell each week to break even.

y= 20x + 200
y= 25x
D= |20 -1|. -20 - (-25)
. |25 -1| D= 5

Dx= |200 -1|. -200 - 0
. |0 -1| Dx= -200

Dy= |20 200|. 0 - 5000
. |25 0 | Dy= -5000

x= Dx/D x= -200/5 x= -40
y= Dy/D y= -5000/5 y= -1000

Is This Right?

Answer 1

20 x - 1 y = -200
25 x - 1 y = 0

D = -20 + 25 = 5

Dx =
| -200 -1 |
| +000 -1 | / 5

= 200/5 = 40 sign ?

Dy =
| 20 -200 |
| 25 +000 | /5

= 5000/5 = 1000