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2. Write down the coefficients of:
2
2
(a) a in 6abc (b) –xy in –7xyz (c) p q in 2p qr (d) bc in − bc
2
5
3. Write the numerical coefficient of terms and coefficient of x in each of the following expressions.
1
2
2
(a) –xyz (b) – xy – 2xy (c) 6x – 2xy z (d) xy z – x
2 3
7
2
4. Identify terms which contain xy and give the coefficient of y .
2
2
2
(a) 3 – xy 2 (b) y + 7xy (c) 3x y – 15xy + 7y – 2xy
2
5. Identify the like and unlike terms in the following sets of algebraic expressions.
2
2
2
2
2
2
(a) a b, ab , –2a b, – 3 a b, 4ab , – a bc (b) 2xy, –3yz, 4yx, – xy, − 1 zy
2 2
2
2
2
2 2
2
2
2
2 2 2
(c) 3x yz, 4xy , –4xyz, –3y x, –7y x (d) p q r , p qr , 4qp r , –8rqp 2
6. Identify the following algebraic expressions as monomial, binomial or trinomial.
6
2
(a) pq + r (b) a – 2ab + b 2 (c) –z (d) x + y 6
(e) –pqr (f) x + 3xy + y 2 (g) xy – x – y (h) x – 1
2
2
2
2
(i) 7 (j) t – 3t + 8 (k) x + y 2 (l) 1 – x – x 2
7. A taxi service charges `10 per km and levies a fixed charge of `50. Write an algebraic expression for
the above situation, if the taxi is hired for x km.
8. Mangoes are to be transferred from a larger basket into smaller baskets. When a larger basket is
emptied, heaps from it fill three smaller baskets and still 16 mangoes remain outside. If the number
of mangoes in a small basket are taken to be x, what is the number of mangoes.
Finding the Value of an Expression
We know that the perimeter of an equilateral triangle = 3 × length of its sides.
Let consider a is the length of the side of an equilateral triangle.
Therefore, perimeter of the equilateral triangle = 3 × a = 3a, where a is the length of a a
its side.
Then, what will be the perimeter of an equilateral triangle whose side is 4 cm?
a
Here, obviously we wish to find value of 3a which represent the perimeter of the
equilateral triangle when a = 4 cm.
So, to find the perimeter of the equilateral triangle, we put a = 4 cm in the expression 3a that is
3 × 4 cm = 12 cm.
l
Therefore, perimeter of the equilateral triangle = 3 × 4 cm = 12 cm

Similarly, let us take a rectangle whose length and breadth are l and
b units respectively. b b
Therefore, the formula for the perimeter of the rectangle is given
by the expression 2 × (l + b) units. l

If the values of the length and breadth of the rectangle are known, then by using the expression
2 × (l + b) units, we can find the value of the perimeter of the rectangle.

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