SIMULTANEOUS 1

Solve the following equations by substitution method.

x - y = 2

x + 3y = 18

Solution

x - y = 2 ----------- (i)

x + 3y = 18 ---------- (ii)

from equation (i)

x - y = 2

x = 2 + y ----------(iii)

Substitute equation (iii) in (ii) above,

x + 3y = 18

(2 + y)  + 3y = 18  

2 + y + 3y= 18           

2 + 4y = 18    [since y+3y=4y]

4y = 18 - 2

4y = 16

4y = 16

4       4

y = 4

From equation (iii)

x = 2 + y

x = 2 + 4 ----------(iii)

x = 6  

Hence x=6 and y=4.

TRY THIS………………………..

Solve the following equations by substitution method.

x - y = 5

x + 3y = 13