Answer:
Explanation:
1). 2x + y = 12 -----(1)
x = 9 - 2y -------(2)
By substituting the value of x from equation (2) to equation (1)
2(9 - 2y) + y = 12
18 - 4y + y = 12
18 - 3y = 12
3y = 18 - 12
y = 2
By substituting the value of x in equation (2)
x = 9 - 2(2)
x = 9 - 4
x = 5
2). x + 2y = 9 ------(1)
2x + 4y = 20
x + 2y = 10 -------(2)
Since, both the equations are the parallel equations,
Therefore, No solutions will be the answer.
3). x + 3y = 16 -------(1)
2x - y = 11 ---------(2)
Multiply equation (2) by 3 the add to equation (1)
6x - 3y + (x + 3y) = 16 + 33
7x = 49
x = 7
From equation (1),
7 + 3y = 16
3y = 9
y = 3
4). y = 11 - 2x -------(1)
4x - 3y = -13 -------(2)
By substituting the value of y from equation (1) to (2),
4x - 3(11 - 2x) = -13
4x - 33 + 6x = -13
10x = 33 - 13
10x = 20
x = 2
From equation (1)
y = 11 - 2(2)
y = 7
5). y = 10 + x -------(1)
-3x + 3y = 30
-x + y = 10
y = 10 + x ------(2)
Equations (1) and (2) are same.
Therefore, Infinite solutions will be the answer.
6). 2x + y = 11 --------(1)
x - 2y = -7 ---------(2)
Multiply equation (1) by 2 then add to equation (2)
4x + 2y + (x - 2y) = 22 - 7
5x = 15
x = 3
From equation (2)
3 - 2y = -7
2y = 3 + 7
y = 5