Respuesta :
3x + y = 4
2x + y = 5....multiply by -1
--------------
3x + y = 4
-2x - y = -5 (result of multiplying by -1)
-------------add
x = -1
3x + y = 4
3(-1) + y = 4
-3 + y = 4
y = 4 + 3
y = 7
solution is (-1,7)
2x + y = 5....multiply by -1
--------------
3x + y = 4
-2x - y = -5 (result of multiplying by -1)
-------------add
x = -1
3x + y = 4
3(-1) + y = 4
-3 + y = 4
y = 4 + 3
y = 7
solution is (-1,7)
Answer:
(D)(-1,7)
Step-by-step explanation:
We want to solve for x and y in the simultaneous equation
3x+y=4
2x+y=5
Subtract Equation 2 from Equation 1
x=-1
Substitute x=-1 into any of the equations to solve for x.
3x+y=4
3(-1)+y=4
-3+y=4
y=4+3=7
Therefore: (x,y)=(-1,7)