assuming that without typos, you meant
2x + y = -11
3x - 4y = 11
from the first, y = -2x-11
substitute that into the second to get
3x - 4(-2x-11) = 11
3x + 8x + 44 = 11
11x = -33
x = -3
so, y=-2(-3)-11 = -5
On the others, if all else fails, try checking each of the proposed solutions. If you get stuck, show us where, and we can help you along.
QUESTIONS (vvv)
(1) Solve the system by subsitution
2x + y = -11
3 - 4y = 11
(2) Solve the system by elimination
2x + 6 = -12
5x - 5y = 10
(3) What is the solution of the following system?
-3x - 2y = -12
9x + 6y = -9
(4) What is the solution of the following system?
x - y = 11
-x + y = -1
ANSWERS (vv)
(1)
(3, 5)
(–5, –3)
(–3, –5)
(5, 3)
(2)
(2, 1)
(0, –2)
(–2, 0)
(1, 2)
(3)
(2, 1)
no solutions
(–2, –1)
infinitely many solutions
(4)
(–3, –4)
no solutions
infinitely many solutions
(3, 4)
1 answer
1 answer