SIMULTANEOUS EQUATIONS 1

Solve the following equations by substitution method.

6x + y = 27

x +  3y = 13

solution

6x  + y = 27----------- (i)

x + 3y = 13---------- (ii)

from equation (i)

6x + y = 27

y = 27 - 6x ----------(iii)

Substitute equation (iii) in (ii) above,

x + 3y = 13---------- (ii)

x + 3(27 - 6x) = 13

x + 81 - 18x = 13

x - 18x + 81 = 13

x - 18x = 13- 81

-17x  = -68

-17x  = -68

-17       -17

x = 4

From equation (iii)

y = 27 - 6x ----------(iii)

y = 27 – 6(4)

y = 27 – 24

y = 3

Hence x=4 and y=3.

TRY THIS……………

Solve the following equations by substitution method.

3x - y = 11

x  +  2y = 27  answer: x=7, y=10