Question

What is the solution of the system? Use elimination.

3x – 4y = –24
x + y = –1
A. (–4, 3)
B. (0, 6)
C. (3, 4)
D. (4, 3)

Answer 1

3x – 4y = –24 (1)
x + y = –1 (2) ->x=-1-y (3)
let (3) into (1)
so 3*(-1-y)-4y=-24 ->y=3
->x=-1-3=-4

Answer 2

\(\Large \color{MidnightBlue}{\Rightarrow 4x + 4y = -4 }\)
Add both equations.

\(\Large \color{MidnightBlue}{\Rightarrow4x = -28 }\)
\(\Large \color{MidnightBlue}{\Rightarrow x = -4 }\)

Lol we know by now that x = -4 so it is A.

Answer 3

try to get the same amount of x's in each equation or same amount of y's

to do this you have to multiply one equation
so lets say i want the same x's

multiply equation 2 by 3

now i have two equations like this
3x – 4y = –24
3x + 3y = –3

now you will subtract equation 2 from 1

Answer 4

By now, all the options but a are eliminated.

Answer 5

no! it's A