4X-3Y=1
X-2Y=4
5 answers
YES
I would do .....
X-2Y=4 ---> x = 2y + 4
now sub that into the other equation, and its a piece of cake after that
X-2Y=4 ---> x = 2y + 4
now sub that into the other equation, and its a piece of cake after that
ANSWER
x - 2 y = 4 ---> x = 2 y + 4
In first equation replace x by 2 y + 4
4 x - 3 y = 1
4 ( 2 y + 4 ) - 3 y = 1
8 y + 16 - 3 y = 1
5 y + 16 = 1
Subtract 16 to both sides
5 y = - 15
y = - 15 / 5
y = - 3
Put this value in:
x = 2 y + 4
x = 2 ∙ ( - 3 ) + 4
x = - 6 + 4
x = - 2
You also can solve this system by other method.
Multiply second equation by - 4
- 4 x + 8 y = - 16
Add the result to the first equation.
4 x - 3 y = 1
+
- 4 x + 8 y = - 16
_____________
5 y = - 15
y = - 15 / 5 = - 3
Put this value in first equation.
x - 2 y = 4
x - 2 ∙ ( - 3 ) = 4
x + 6 = 4
Subtract 6 to both sides.
x = - 2
Solution is:
x = - 2 , y = - 3
You can write solution as:
( - 3 , - 2 )
In first equation replace x by 2 y + 4
4 x - 3 y = 1
4 ( 2 y + 4 ) - 3 y = 1
8 y + 16 - 3 y = 1
5 y + 16 = 1
Subtract 16 to both sides
5 y = - 15
y = - 15 / 5
y = - 3
Put this value in:
x = 2 y + 4
x = 2 ∙ ( - 3 ) + 4
x = - 6 + 4
x = - 2
You also can solve this system by other method.
Multiply second equation by - 4
- 4 x + 8 y = - 16
Add the result to the first equation.
4 x - 3 y = 1
+
- 4 x + 8 y = - 16
_____________
5 y = - 15
y = - 15 / 5 = - 3
Put this value in first equation.
x - 2 y = 4
x - 2 ∙ ( - 3 ) = 4
x + 6 = 4
Subtract 6 to both sides.
x = - 2
Solution is:
x = - 2 , y = - 3
You can write solution as:
( - 3 , - 2 )
My typo.
First value of x then value of y
You can write solution as:
( - 2 , - 3 )
First value of x then value of y
You can write solution as:
( - 2 , - 3 )