Question

HELP PLS
solve system of equations
9x+4y = -13
8x+5y=0

Answer 1

are you familiar with matricies?

Answer 2

no :(

Answer 3

What you want to do is get rid of one of the variables

Answer 4

I'd recommend using the second equation since the constant is 0

Answer 5

9x+4y = -13
8x+5y=0

I'll use elimination:

45x + 20y = -65
32x + 20y = 0

13x = -65

x = -5

9(-5) + 4y = -13

-45 + 4y = -13

4y = 32

y = 8

(-5, 8)

Answer 6

@a1234 is correct.
Just ignore me. =)

Answer 7

how did you get 45x + 20y = -65
32x + 20y = 0

????

Answer 8

using elimination as shown by a1234 -> \(\large \begin{array}{llll}
9x+4y=-13&{\color{red}{ \times 5}}\implies & \quad 45x\cancel{+20y}=-65\\
8x+5y=0&{\color{red}{ \times -4}}\implies &-32x\cancel{-20y}=\quad 0\\
\hline\\
&&13x\qquad \qquad =-65
\end{array}\)