Ex 1A:

b)a^2-9a^2+a^2-9a

c)3x^2+5y-3xy+(-5x)

d)x^2-(a+b)x+ab

Consider the cylindrical tank:

Diameter=1.4m

Radius=r

1

=

2

1.4

=0.7m

Height =h

1

=2.1=

10

21

m

Consider the cylindrical pipe:

Diameter=3.5cm=

10

35

cm=

2

7

cm

Radius=r

2

=

4

7

cm=

400

7

m

Speed =h

2

=2mper sec

∴ Time taken to fill the tank=

Volumeofcylindricalpipe

Volumeofcylindricaltank

=

πr

2

2

h

2

πr

1

2

h

1

=

π×

400

7

×

400

7

×2

π×

10

7

×

10

7

×

10

21

=

10

7

×

10

7

×

10

21

×

7

400

×

7

400

×

2

1

=1680secs

=

60

1680

minutes

=28minutes