## FlyinSolo_424 2 years ago Choose the value of the y determinant (Dy) in the following system. 3x – y = 7 2x + 5y = 4

1. bman123

are there choices

2. FlyinSolo_424

17 39 28 -2

3. FlyinSolo_424

@bman123

4. exploringphysics

what do you mean by y [dy] for the set of eq. ??

5. exploringphysics

hey @FlyinSolo_424

6. FlyinSolo_424

oh sorry. and like d (little y) instead of ^y it would be the other way

7. FlyinSolo_424

|dw:1356062104599:dw|

8. FlyinSolo_424

@exploringphysics

9. satellite73

list the coefficients without the $$y$$ you get $3,7$$2,4$ then $$D_y=3\times 4-7\times 2$$ if i remember correctly

10. FlyinSolo_424

im confused @satellite73

11. satellite73

did you see how i got this $3,7$$2,4$?

12. exploringphysics

[3 7] [2 4] id required one can you solve this ?

13. wio

We start out with the system:$\begin{array}{cccc} 3x &–& y &=& 7 \\ 2x &+& 5y &=& 4 \end{array}$ We have our matrix by taking coefficients: $\begin{bmatrix} 3&-1\\ 2&5 \end{bmatrix}$We have our answer column: $\begin{bmatrix} 7\\4 \end{bmatrix}$We replace the y column with the answer column:$\begin{bmatrix} 3&7\\ 2&4 \end{bmatrix}$Then we find the determinant:$3\times 4 - 7 \times 2$