Simple Equations
Write the statement as an equation
5 less than twice a number x is 7
x = 6
3/2 times a number n is 15
n=5
Solve the equations and check the result
x-6 =11
2x-3 =13
2x +10 =22
-5x -6 = -11
x3 +9 =14
3x-4 = 8-x
x2 + x3 =1
x4 = 9/8
3(x+2) -2(x-1) =11
i) x-6=11
= x= 11+6
= x=17
ii) 2x-3=13
=2x= 13+3
=2x=16
=x=8
iii) 2x+10=22
= 2x=22-10
= 2x= 12
= x=6
iv)-5x-6=-11
= -5x= -11+6
= -5x= -7
= x= 7/5
vi) 3x-4= 8-x
= 3x-x=8+4
= 2x=12
= X=6
ix) 3(x+2) - 2(x-1)= 11
= 3x+6 -2x + 2 = 11
= x+8=11
=x=3
1. The sum of three times a number and 15 is 42. Find the number.
3x+15=42
3x=42-15
3x= 27
x=27/3
So, x=9
2. If 3 is subtracted from twice a number, the result is 19. Find the number.
2x-13=19
2x=32
x=16
the no. is 16
3. Gagan’s father is 45 years old. He is 5 years older than two times Gagan’s age. What is Gagan’s age?
2x + 5 = 45
2x = 45 - 5 = 40
x = 40/2 = 20
4. The sum of three consecutive even numbers is 276. Find the numbers.
90, 92 and 94.
5. The age of a father is 40 years more than that of his son. After 5 years, father’s age will be thrice his son’s age. Find their present ages.
3b - b = 40
2b = 40
b = 20
Son’s present age = 20 - 5 = 15
Father’s present age = 60 - 5 = 55
Exponents
Write the following in exponential form
i. 3x 3 x 3 x3
3
ii. (-2) x .(-2) x .(-2) x .(-2) x .(-2) x (-2)
iii. -32243
Simplify
i. (-1)3 x (-2)3 ii. (-9)3 iii. (-2/3)3
Which is greater ? 23 or 32
Simplify each of the following
(23 x 2 )2
58 / 55 x53
(27 / 23 )x25
{(22 )4 x 38 }x58
(4 x 34 x24 ) / (2 x 25 )
(36 x a5) / (92 x a3)
2 x 34 x25/ (9x 42 )
Write the numbers in standard form
i. 149,600, 000,000 m
ii. 1,27,56,000 m
Write the following in usual form.
i. 4.356 x 107
ii. 7.253 x 1011
Answers
Write the statement as an equation
5 less than twice a number x is 7
x = 6
3/2 times a number n is 15
n=5
Solve the equations and check the result
x-6 =11
2x-3 =13
2x +10 =22
-5x -6 = -11
x3 +9 =14
3x-4 = 8-x
x2 + x3 =1
x4 = 9/8
3(x+2) -2(x-1) =11
i) x-6=11
= x= 11+6
= x=17
ii) 2x-3=13
=2x= 13+3
=2x=16
=x=8
iii) 2x+10=22
= 2x=22-10
= 2x= 12
= x=6
iv)-5x-6=-11
= -5x= -11+6
= -5x= -7
= x= 7/5
vi) 3x-4= 8-x
= 3x-x=8+4
= 2x=12
= X=
Answer:
Write the statement as an equation
5 less than twice a number x is 7
x = 6
3/2 times a number n is 15
n=5
Solve the equations and check the result
x-6 =11
2x-3 =13
2x +10 =22
-5x -6 = -11
x3 +9 =14
3x-4 = 8-x
x2 + x3 =1
x4 = 9/8
3(x+2) -2(x-1) =11
i) x-6=11
= x= 11+6
= x=17
ii) 2x-3=13
=2x= 13+3
=2x=16
=x=8
iii) 2x+10=22
= 2x=22-10
= 2x= 12
= x=6
iv)-5x-6=-11
= -5x= -11+6
= -5x= -7
= x= 7/5
vi) 3x-4= 8-x
= 3x-x=8+4
= 2x=12
= X=6
ix) 3(x+2) - 2(x-1)= 11
= 3x+6 -2x + 2 = 11
= x+8=11
=x=3
1. The sum of three times a number and 15 is 42. Find the number.
3x+15=42
3x=42-15
3x= 27
x=27/3
So, x=9