Question

Find the missing term.

7-147 × 798 = 718 × 7-38 ×___________?

A.7^(-20)
B.7^22
C.7^(-29)
D.7^58

How do I do this

Answer 1

Answer: Option 'C' is correct.

The missing term is
`7^(-29)=x`

Explanation:

Since we have given that

`7^(-147)* 7^(98)=7^(18)* 7^(-38)* x`

We need to find the missing part i.e. x.

We will use "Exponential law " :

`a^m* a^n=a^(m+n)`

So, it becomes,

`7^(-147)* 7^(98)=7^(18)* 7^(-38)* x\\\\7^(-147+98)=7^(18-38)* x\\\\7^(-49)=7^(-20)* x\\\\7^(-49)/ 7^(-20)=x\\\\7^(-49-(-20))=x\\\\7^(-49+20)=x\\\\7^(-29)=x`

Hence, the missing term is
`7^(-29)=x`

Therefore, Option 'C' is correct.

Answer 2

Find the missing term.7-147 × 798 = 718 × 7-38 × M
7^-147 * 7^98 = 7^18 * 7^-38 * M
7^(-147+98) = 7^(18 + -38)
7^-49 = 7^-20 * M
M = 7^-49 / 7^-20
M = 7^(-49 + 20)
M = 7^-29

So the correct answer is C.7^(-29)