Question

Solve the following simultaneous equations
(i) 2x + y = 5 ; 3x - y = 5
(ii) x - 2y = -1 ; 2x- y = 7
(iii) x + y = 11 ; 2x - 3y = 7
(iv) 2x + y = -2 ; 3x - y = 7
(v) 3x - 4y=7 ; 5x + 2y=3

Answer 1

Step-by-step explanation:

(i) 2x+y=5

y=5-2x..eq1

3x-y=5...eq2

(putting value of y in eq2 from eq1)

so, 3x-(5-2x)=5

3x-5+2x=5

5x-5=5

5x=10

x=10/5

x=2

(putting value of x in eq1)

2×2+y=5

4+y=5

y=5-4

y=1

Answer 2

Answer:

i) 2x + y = 5

+ 3x - y = 5

y gets cancelled because we are adding the equations and it's sign is not same.

So by adding 2x and 3x we get 5x = 10

5x =10

x = 10 /5

x =2

substitute x=2 in the first equation.

2x + y = 5

2 * 2 + y =5

4 + y=5

y =5-4

y =1

therefore (x, y) = (2, 1)

Step-by-step explanation:

Similarly,

ii) (x, y) = ( 5 , 3)

iii) ( x, y) = ( 8, 3)

iv) (x, y) = (1 , - 4)

v) ( x, y) = (1 , -1)