pair of linear equations in two variables class 10 solutions Exercise 3.4

Pair of Linear Equations in Two Variables Class 10 Solutions Exercise 3.4

RD Sharma Class 10 Solutions Pair Of Linear Equations In Two Variables Ex 3.4

Solve each of the following systems of equations by the method of cross multiplication.
Question 1.
x + 2y + 1 = 0
2x – 3y – 12 = 0 (C.B.S.E. 1992)
Solution:

Question 2.
3x + 2y + 25 = 0
2x + y + 10 = 0 (C.B.S.E. 1992)
Solution:

Question 3.
2x + y = 35
3x + 4y = 65 (C.B.S.E. 1993)
Solution:

Question 4.
2x – y = 6
x – y = 2 (C.B.S.E. 1994)
Solution:

Question 5.
\(\frac { x+y }{ xy } =2,\quad \frac { x-y }{ xy } =6\)
Solution:

Question 6.
ax + by = a – b
bx – ay = a + b
Solution:
ax + by = a – b
bx – ay = a + b

Question 7.
x + ay = b
ax – by = c
Solution:
x + ay = b

Question 8.
ax + by = a²
bx + ay = b²
Solution:

Question 9.

Solution:

Question 10.

Solution:

Question 11.

Solution:

Question 12.

Solution:

Question 13.
\(\frac { x }{ { a } } +\frac { y }{ b } =a+b\)
\(\frac { x }{ { { a }^{ 2 } } } +\frac { y }{ { b }^{ 2 } } =2\)
Solution:

Question 14.
\(\frac { x }{ { { a } } } =\frac { y }{ { b } }\)
ax + by = a² + b²
Solution:

Question 15.
2ax + 3by = a + 2b
3ax + 2by = 2a + b
Solution:

Question 16.
5ax + 6by = 28
3ax + 4by = 18
Solution:

Question 17.
(a + 2b) x + (2a – b) y = 2
(a – 2b) x + (2a + b) y = 3
Solution:

Question 18.

Solution:

Question 19.

Solution:

Question 20.
(a – b) x + (a + b) y = 2a² – 2b²
(a + b) (x + y) = 4ab
Solution:

Question 21.
a²x + b²y = c²
b²x + a²y = d²
Solution:

Question 22.
ax + by = \(\frac { a + b }{ 2 }\)
3x + 5y = 4
Solution:

Hence x = \(\frac { 1 }{ 2 }\) , y = \(\frac { 1 }{ 2 }\)

Question 23.
2 (ax – by) + a + 4b = 0
2 (bx + ay) + b – 4a = 0 (C.B.S.E. 2004)
Solution:

Question 24.
6 (ax + by) = 3a + 2b
6 (bx – ay) = 3b – 2a (C.B.S.E. 2004)
Solution:

Question 25.
\(\frac { { a }^{ 2 } }{ x } -\frac { { b }^{ 2 } }{ y } =0\)
\(\frac { { a }^{ 2 }b }{ x } -\frac { { b }^{ 2 }a }{ y } =a+b\quad ,\quad x,y\quad \neq 0\)
Solution: