Question

Solve using Cramer's Rule.
2x + 2y = –8
7x + 4y = –1

Answer 1

4x+4y=-16
- 7x+4y= -1
-------------
-3x = -15
x = 5

2(5) +2y=-8
10+2y=-8
2y=-18

y=-9

Answer 2

Thank you

Answer 3

you're welcome :)

Answer 4

can you help with another?

Answer 5

Sure. Which is it?

Answer 6

Solve the system of equations.
–5x + 3y + 2z = 19
x + 4y + 3z = –27
15x – 9y – 6z = –55

Answer 7

Hold on. Let me see.

Answer 8

I'm sorry... I can't help much there! But I'm sure someone will be able if you post this question up

Answer 9

ok thanks

Answer 10

Did you want it solved by Cramer's rule?

Answer 11

By Cramer's rule it would be:
2x + 2y = –8
7x + 4y = –1
\[D=\det \left[\begin{matrix}2 & 2 \\ 7 & 4\end{matrix}\right] = 2*4-7*2=-6\]
\[Dx=\det \left[\begin{matrix}-8 & 2 \\ -1 & 4\end{matrix}\right] = -32+2 = -30\]
and
\[Dy=\det \left[\begin{matrix}2 & -8 \\ 7 & -1\end{matrix}\right] = -2+56 = 54\]
So
x=Dx/D=-30/(-6)=5
y=Dy/D=54/(-6)=-9