Vidaara.orgClass 9 · Mathematics
CodeVID-M09-19-CRS-01
Cross-Multiplication - Assignment
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Section A carries 1 mark each, Section B 2 marks, Section C 3 marks and Section D 5 marks.
- Show all working for Sections B, C and D. Only final answers are given at the end — for full solutions, raise your doubts with your teacher.
Section A — Multiple Choice Questions
5 × 1 = 5 marks
1.
The standard form for cross-multiplication is:
- A.$ax+by=0$
- B.$ax+by+c=0$
- C.$ax=by$
- D.$y=mx+c$
2.
The common denominator for $x$ and $y$ is:
- A.$a_1b_2-a_2b_1$
- B.$a_1+b_2$
- C.$c_1c_2$
- D.$a_1a_2$
3.
Cross-multiplication expresses $x,y$ via the:
- A.graph
- B.coefficients
- C.roots
- D.squares
4.
If $a_1b_2-a_2b_1=0$, there is no:
- A.variable
- B.unique solution
- C.constant
- D.line
5.
The method solves a pair of ___ equations.
- A.quadratic
- B.linear
- C.cubic
- D.exponential
Section B — Short Answer (2 marks)
4 × 2 = 8 marks
6.
Write the standard form needed for cross-multiplication.
7.
For $x+y-5=0$ and $x-y-1=0$, identify $a_1,b_1,c_1$.
8.
What is the common denominator for $x$ and $y$?
9.
When does the pair have no unique solution?
Section C — Short Answer (3 marks)
4 × 3 = 12 marks
10.
Solve by cross-multiplication: $2x+3y-13=0$ and $x-y+1=0$.
11.
Solve: $x+y-7=0,\ 2x-y-2=0$.
12.
Solve: $3x-y-7=0,\ 2x+y-8=0$.
13.
Solve: $x-2y-1=0,\ 2x+y-7=0$.
Section D — Long Answer (5 marks)
2 × 5 = 10 marks
14.
Solve by cross-multiplication: $2x+3y=17$ and $3x-2y=6$.
15.
Solve by cross-multiplication: $4x-3y=11$ and $3x+7y=-1$.
Answer Key
Section A — Multiple Choice Questions
- (B) $ax+by+c=0$
- (A) $a_1b_2-a_2b_1$
- (B) coefficients
- (B) unique solution
- (B) linear
Section B — Short Answer (2 marks)
- $ax+by+c=0$.
- $a_1=1,\ b_1=1,\ c_1=-5$.
- $a_1b_2-a_2b_1$.
- When $a_1b_2-a_2b_1=0$.
Section C — Short Answer (3 marks)
- $x=2,\ y=3$.
- $x=3,\ y=4$.
- $x=3,\ y=2$.
- $x=3,\ y=1$.
Section D — Long Answer (5 marks)
- $x=4,\ y=3$.
- $x=2,\ y=-1$.
Generated by Vidaara.org · Assignment VID-M09-19-CRS-01 · vidaara.org