Exercise 3.12: Solving by Elimination Method

Elimination Method of Solving simultaneous linear equations in Two Variables

Exercise 3.12

1. Solve by the method of elimination

(i) 2x–y = 3; 3x + y = 7

(ii) x–y = 5; 3x + 2y = 25

(iii) x/10 + y/5 = 14; x/8 + y/6 = 15

(iv) 3(2x + y) = 7xy; 3(x + 3y) = 11xy

(v) 4/x + 5y = 7; 3/x + 4 y = 5

(vi) 13x + 11y = 70; 11x + 13y = 74

2. The monthly income of A and B are in the ratio 3:4 and their monthly expenditures are in the ratio 5:7. If each saves ₹ 5,000 per month, find the monthly income of each.

3. Five years ago, a man was seven times as old as his son, while five year hence, the man will be four times as old as his son. Find their present age.