Need help with #12
Please help

Answer:#1 is D

Step-by-step explanation:angles must equal 180 and yk that the angle under e is 39 so 180-39 =141

14 + 28 + 42 + 56 + … 280

= 14 (1 + 2 + 3 + 4 + … + 20)

= 14 × 20 × 21 / 2

= 2940

where we use the well-known identity,

[tex]\displaystyle \sum_{i=1}^ni = 1 + 2 + 3 + \cdots + n = \dfrac{n(n+1)}2[/tex]

Answer:

Exponential notation is a powerful way to express repeated

multiplication of the same number. Specifically, powers of 10

express very large and very small numbers in a manner which is

convenient to read, write and compare.

• For any non-zero integer a, a–m 1

m a

=

• Laws of exponents are

(a) am × an = am+n

(b) am ÷ an = am–n

(c) (am)

n = amn

(d) am × bm = (ab)

m

(e) a° = 1, where a ≠ 0

(f)

m m

m

a a

b b

  =   

• Numbers can be expressed in expanded form by using exponents.

• Very large and very small numbers can be expressed in standard

form.

• Standard form is also called scientific notation form.

Step-by-step explanation:

Example 1 : Multiplicative inverse of 27 is

(a) 2–7 (b) 72 (c) – 27 (d) – 27

Solution : The Correct answer is (a).

Example 2 : The human body has about 100 billion cells. This number

can be written in exponential form as

(a) 10–11 (b) 1011 (c) 109 (d) 10–9

Solution : The correct answer is (b).

In examples 3 to 5, fill in the blanks to make the statements true.

Example 3 :

4

4 5 (– 4) ______ 4

  × =    

Solution : 54

Example 4 : ( ) ( ) 2 3 –3 –2 2 3 _____ × =

Solution : 6–6

Example 5 : The distance between earth and sun is 150 million

kilometres which can be written in exponential form as

_______.

Solution : 1.5 × 108 km

In examples 6 and 7, state whether the statements are true (T) or false (F):

Example 6 : Very small numbers can be expressed in standard form

using positive exponents.

Solution : False.

Example 7 : (–10) × (–10) × (–10) × (–10) = 10–4

Solution : False.

Step-by-step explanation: