13-16 pls I don’t understand

13. 1

14. 42

15. 65

Step-by-step explanation:

13.

If the average of two numbers is 1, then the sum of those two numbers is 2. As 2*1 is 2, and the average is found by dividing the sum by the amount of numbers.

Only one number is an integer and has a reciprocal that is an integer, the number being 1.

1/1 = 1

1/1 = 1

Average:

1+1 = 2

2/1 = 1

Therefore the answer is 1.

14.

If we multiply everything by 7x, we'd get

7 + x = 49

subtract 7 on both sides

x = 42

15.

If

pg = 50 and gr = 15

then

pg + gr = 65

factoring that would give you

g(p+r) = 65

I can't see 16 but good luck!

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.

it would open into a square depending on the type of envelope i’m not sure about the second part