Posted by **Jon** on Monday, February 18, 2008 at 11:39am.

Solve the matrix equation 2x + 5y = 1

x + 3y = 0 for y.

A)1

B)3

C)-3

D)-1

I chose D

2x + 5y = 1

y = 5 - 2x

x + 3(5 - 2x)= 0

x + 15 - 6x = 0

7x = 15

x = 15/7

I know that's wrong I don't know what to do

- Algebra(1 of 3) -
**drwls**, Monday, February 18, 2008 at 12:05pm
Your very first step is incorrect. Try this:

x + 3y = 0

x + 5/2 y = 1/2

Now subtract the last eq. from the first.

y/2 = -1/2

y = -1

- Algebra(1 of 3) -
**Reiny**, Monday, February 18, 2008 at 12:09pm
your solution is "riddled" with errors

2x + 5y = 1 solved for y is y = (1-2x)/5

not y = 5 - 2x like you had.

Even if it had been right, x + 15 - 6x = 0

becomes

-5x = -15 , not 7x=15 like you had

lets start over.

Why not solve the second equation for x? (look for the "single" variable)

x = -3y sub that back into the first

2(-3y) + 5y = 1

-y = 1

y = -1 looks like your D was the right guess.

- Algebra(1 of 3) -
**Anonymous**, Saturday, April 23, 2011 at 8:08am
- 15 x ² + 2x + 13 = 0

## Answer This Question

## Related Questions

- Algebra II (Matrices) - My book doesn't solve it like a linear equation, they ...
- math,algebra II - I have to work with these types of problems dealing with ...
- ALGEBRA 2 (matrix equation) - MATRIX EQUATION [ 3x ] [ 10+2y ] [ y ] = [ 5-x ] ...
- Maths: Algebra Matrices Class 12th - matrix{{0, 1, -1}, {2, 1, 3}, {1, 1, 1}} ...
- science - 1 A ……... is a rectangular array of numbers that are ...
- Algebra - Solve the matrix equation: |4 -5||m|=|32| |1 2||n|=|-5| I don't get it
- Algebra II - Can someone please help me with this problem. Given Matrix Y= 2 -7 ...
- Algebra 2(check pt 4) - 1)Cramer's Rule is used to solve the system of equations...
- Algebra - 1)If y varies inversely as x and y = 3, when x = 6. Find y when x = 36...
- Math - Hi! I need help with these two questions. Thanks! :) 1.) Can we multiply ...

More Related Questions