Question

5.01 *10^-7-30*10^-9

Answer 1

Answer:

$\large\boxed{4.71\times10^{-7}}$

Step-by-step explanation:

$5.01\times10^{-7}-30\times10^{-9}\qquad\text{use}\ a^n\cdot a^m=a^{n+m}\\\\=5.01\times10^{-9+2}-30\times10^{-9}\\\\=5.01\times10^{-9}\cdot10^2-30\times10^{-9}\\\\=(5.01\cdot10^2)\times10^{-9}-30\times10^{-9}\\\\=(5.01\cdot100)\times10^{-9}-30\times10^{-9}\\\\=501\times10^{-9}-30\times10^{-9}\qquad\text{distribute}\\\\=(501-30)\times10^{-9}\\\\=471\times10^{-9}\\\\=4.71\cdot10^2\times10^{-9}\qquad\text{use}\ a^n\cdot a^m=a^{n+m}\\\\=4.71\times10^{2+(-9)}\\\\=4.71\times10^{-7}$

or

$5.01\times10^{-7}-30\times10^{-9}\\\\=5.01\times10^{-7}-30\times10^{-7+(-2)}\\\\=5.01\times10^{-7}-30\times10^{-7}\cdot10^{-2}\\\\=5.01\times10^{-7}-(30\cdot10^{-2})\times10^{-7}\qquad\text{use}\ a^{-n}=\dfrac{1}{a^n}\\\\=5.01\times10^{-7}-\left(30\cdot\dfrac{1}{10^2}\right)\times10^{-7}\\\\=5.01\times10^{-7}-\left(30\cdot\dfrac{1}{100}\right)\times10^{-7}\\\\=5.01\times10^{-7}-(30\cdot0.01)\times10^{-7}\\\\=5.01\times10^{-7}-0.3\times10^{-7}\qquad\text{distribute}\\\\=(5.01-0.3)\times10^{-7}\\\\=4.71\times10^{-7}$