Algebraic Methods of Solving a Pair of Linear Equations - Substitution Method

5 books and 7 pens together cost Rs 79 whereas 7 books and 5 pens together cost Rs 77. Find the total cost of 1 book and 2 pens.

A train covered a certain distance at a uniform speed. If the train would have been 6 km/h faster, it would have taken 4 hours less than the scheduled time. And, if the train was slower by 6 km/h it would have taken 6 hours more than the scheduled time. Find the length of the journey.

Solve the following system of equations by eliminating ‘y’ (by substitution) :

2x + y = 0

17x – 11y – 8 = 0

Solve the following systems of equations:

2(3u − ν) = 5uν
2(u + 3ν) = 5uν

One says, “Give me a hundred, friend! I shall then become twice as rich as you.” The other replies, “If you give me ten, I shall be six times as rich as you.” Tell me what is the amount of their respective capital

Solve the following systems of equations:

`2/x + 3/y = 9/(xy)`

`4/x + 9/y = 21/(xy), where x != 0, y != 0`

Solve the following systems of equations:

`"xy"/(x + y) = 6/5`

`"xy"/(y- x) = 6`

Solve the following systems of equations:

3x − 7y + 10 = 0
y − 2x − 3 = 0