This is the Important question of class 10 Based on Equation of a Straight Line Chapter of M.L Aggarwal book for ICSE BOARD.

Two parallel lines are given, So find the relation connecting a and b.

This is the Question Number 03, Exercise 12.2 of M.L Aggarwal.

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# Lines 2x – by + 5 = 0 and ax + 3y = 2 are parallel. Find the relation connecting a and b.

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Given lines are: 2x – by + 5 = 0 and ax + 3y = 2

If two lines to be parallel then their slopes must be equal.

In equation 2x – by + 5 = 0,

by = 2x + 5

y = (2/b) x + 5/b

So, the slope of the line (m

_{1}) = 2/bAnd in equation ax + 3y = 2,

3y = -ax + 2

y = (-a/3) x + 2/3

So, the slope of the line (m

_{2}) = (-a/3)As the lines are parallel

m

_{1}= m_{2}2/b = -a/3

6 = -ab

Hence, the relation connecting a and b is ab + 6 = 0