SIMULTANEOUS EQN 1

Solve the following equations by substitution method.

x + y = 10

2x + y = 16

Solution

x + y = 10 ----------- (i)

2x + y = 16 ---------- (ii)

from equation (i)

x + y = 10

x = 10 – y ----------(iii)

substitute equation (iii) in (ii) above,

2(10 – y) + y = 16

20–2y  + y = 16  

20 – y = 16           [since –2y+y = -y]

20 –16 = y   

4 = y          

      

So; y = 4

From equation (iii)

x = 10 – 4 ----------(iii)

x = 6

Hence x=6 and y=4.

TRY THIS………………………..

Solve the following equations by substitution method.

5x – y = 11

x  +  y = 7

Answer: x=3;   y=4