Answer:


Step-by-step explanation:
<u>Scientific notation</u>
where:
is any positive or negative <u>whole number</u>.
To convert a number into scientific notation, <u>move</u> the decimal point to the <u>left or right</u> until there is <u>one digit</u> to the left of the decimal point.
The number of times you have moved the decimal point is
.
- If the decimal point has moved to the <u>left</u>,
is positive. - If the decimal point has moved to the <u>right</u>,
is negative.
To convert 500,000,000,000 into scientific notation, move the decimal point <u>11 places to left</u>, so a = 5. As we have moved the decimal point 11 places to the left, the exponent "n" is 11 and is <u>positive</u>.

To convert 0.00000000005 into scientific notation, move the decimal point <u>11 places to the right</u>, so a = 5. As we have moved the decimal point 11 places to the right , the exponent "n" is 11 and is <u>negative</u>.

Learn more about scientific notation here:
brainly.com/question/28235385
Answer & Step-by-step explanation:
2a - b : 2a + b = 1 : 2
2a - b = 1
- Elimination
2a + b = 2
-b - (b) = -1
-2b = -1
b = 0.5
---------------------------------------------------------------------------------
2a + b = 2 Substitution
2a + 0.5 = 2
2a = 1.5
a = 0.75
--------------------------------------------------------------------------------------
a:b
0.75 : 0.5
or
3/4 : 1/2
Hope this helps!!!
The second answer, cause it best shows the equation, but they just moved the numbers around. It is also the only equation with all the same numbers used in the original equation, too