SIMULTANEOUS EQUATIONS 1

Solve the following equations by substitution method.

x + y = 13

x + 3y = 27

Solution

x + y = 13 ----------- (i)

x + 3y = 27 ---------- (ii)

from equation (i)

x + y = 13

x = 13 - y ----------(iii)

substitute equation (iii) in (ii) above,

x + 3y = 27

(13 - y)  + 3y = 27

13 + 2y = 27            [since –y+3y=2y]

2y = 27 - 13

2y = 14

2      2

y = 7

From equation (iii)

x = 13 - y ----------(iii)

x = 13 - 7

x = 6

Hence x=6 and y=7.

TRY THIS………………………..

Solve the following equations by substitution method.

x + y = 10

2x + y = 13