express 0.0000000015 in standard form?

1.5 multiplied by 10 to the power of -9

To get standard form you must get a number between 1 and 10 and the power is the number of decimal spaces you have to move the decimal point if you move the point from left to right it is a negative power and if you move it from right to left it would be a positive power

Example1: 130000.0 would be 1.3 multiplied by 10 to the power of 5
Example2: 0.000031 would be 3.1 multiplied by 10 to the power of -5

1.5 X 10^-9

0.0000000015 = 1.5 x10^-9

1.5 x 10^-9

1.5 x 10^(-9)

0.0000000015
= 1.5 x 0.000000001
= 1.5 x 1/10^9
= 1.5 x 10^(-9)

0.0000000015 = 1.5 x 10^ -9

I assume you mean scientific notation

1.5 * 10^-9

1.5 x 10^-9

I would say 15 times 10 to the minus three.

yotta Y 1,000,000,000,000,000,000,000,000 1024
zetta Z 1,000,000,000,000,000,000,000 1021
exa E 1,000,000,000,000,000,000 1018
peta P 1,000,000,000,000,000 1015
tera T 1,000,000,000,000 1012
giga G 1,000,000,000 109
mega M 1,000,000 106
kilo k 1,000 103 hecto h 100 102
deca da 10 101 1 100
deci d 0.1 10¯1
centi c 0.01 10¯2
milli m 0.001 10¯3
micro µ 0.000001 10¯6
nano n 0.000000001 10¯9
pico p 0.000000000001 10¯12
femto f 0.000000000000001 10¯15
atto a 0.000000000000000001 10¯18
zepto z 0.000000000000000000001 10¯21
yocto y 0.000000000000000000000001 10¯24