Maths text book d1

Ex#7a-7h

Pg#140

Q1.find the solution of each of the following equations by observation: (a)3a-4=a

3a-4+4=a+4

3a-a=a-a+4

2a=4

a=2

(b)50-5a=10

50-50-5a=10-50

-5a=-40

a=8

(c)24 =3

a

24 x a=3xa

a

24=3a

a=8

(d)1 a -1 a=2

2 3

1 a – 1 a=2 x 3

2 3

1 a – 1a=6 x 2

2

1a-1a=12

a=12

Ex 7B

Pg#144

Q1.Solve the following equations:

(a)a+5=17

a+5-5=17-5

a=12

(b)4a=-20

4a=-20

4 4

a=-5

(c) k-1.6=-0.4

K-1.6+1.6=-0.4+1.6

K=1.2

Q2.solve the following equations:

(a)3x-2=4

3x-2+2=4+2

3x=6

3 x= 6

3 3

x=2

(b) 4+9x=22

4-4+9x=22-4

9x=18

9 x=18

9 9

x=3

(c)11-2k=17

11-11-2k=17-11

-2k=6

-2 k=6

-2 -2

K=-3

(d)3x-1.7=4.3

3x-1.7+1.7=4.3+1.7

3x=6

3 x=6

3 3

x=2

Q3.solve the following equation:

(a)3(x+3)=15

3x+9=15

3x+9-9=15-9

3x=6

3x=6

3 3

x=2

(b) 4(h-2)=28

4h-8=28

4h-8+8=28+8

4h=36

4 h=36

4 4

h=9

(c)3(5-4x)=21

15-12x=21

15-15-12x=21-15

-12x=21-15

-12x=6

-12x=6

-12 -12

x=-0.5/-1

2

Ex7C

Pg#147

Q1.Solve the following equation.

(a)3a=2a+4

3a-2a=2a-2a+4

a=4

(b)4x=15-x

4x+x=15-x+x

5x=15

5x=15

5 5

x=3

(c)6x+5=9x-19

6x+5-5=9x-19-5

6x=9x-24

6x-9x=9x-9x-24

-3x=-24

x=8

Q2.Solve the following equations:

(a)2(c-4)=3(c-2)

2c-8=3c-6

2c-8+8=3c-6+8

2c=3c+2

2c-3c=3c-3c+2

-c=2

C=-2

(b)2(3a-4)=5(a+6)

6a-8=5a+30

6a-8+8=5a+30+8

6a=5a+22

6a-5a=5a-5a+38

a=38

(c)9(2x+7)=11(x+14)

18x+63=11+154

18x+63-63=11x+154-63

18x=11x+91

18x-11x=11x-11x+91

7x=91

7x=91

7 7

x=13

Q3.Solve the following equations:

(a)a+3=4

3

a+3-3=4-3

3

a x3=1x3

3

a=3

(b)x -2=3

5

x -2+2=3+2

5

x=5

5

X x5=5x5

5

x=25

(c)4-2x=-2

3

4-4-2x=-2-4

3

-2x x3=-6x3

3

-2x=-18

-2 -2

x=9

Q4.Solve the following equations:

(a)x+x=12

5

x+x x5=12x5

5

2x=60

2x=60

2 2

x=30

(b)2 =2(3x-7)

5

2=6x-14

5

2x5=6x-14x5

5

2=6x-70

6x=-2-70

6x=-72

6x=72

6 6

x=12

(c) 5-2x=2

7

5-2x x7=2x7

7

5-2x=14

5-5-2x=14-5

-2x=9

-2 -2

x=4.5/4 1

2

Ex7d

Pg#150

Take the value of π as 3 1 where

necessary. 7

Q1.If v=1 AH, find when a=43 and h=6.

3

v=1 x43x6

3

V= 1 x258

3

V=258

3

V=86

Q2.If F =9c+32, find F when c=30.

5

F=9 x 30 +32

5

F= 270 +32

5

F=54+32

F=86

Q3.If K=x+y, find X when K=12 and

3

Y=4 .

12=x + 4

3

12 x 3=x + 4 x 3

3

36 - 4=x + 4 -4

X=32

Ex 7E

Pg#151

Q1.Using the letter suggested, construct a simple formula in each case: (a)The sum (S) of three numbers a,b,c.

S=a+b+c

(b)The product (P) of two numbers x and y.

P=X x y

P=xy

(c)The difference between the ages of two boys; one being A years old and the other E years old. D=a-e

Ex7F

Pg#153

Q1.How many grams are there in 5kg? How many grams are there in x kg? Grams in 5kg=5 x 1000gm

Grams in x kg=1 x 1000gm

X kg=1000gm

Q2.Four tennis balls have the mass of m kg.Find the mass of each ball. Mass of 4 tennis balls=m kg

Mass of each ball=1 m kg

4...