I need help please and thank you i will mark brainlest!

Answer:
[tex]2.2\times 10^{7}[/tex]
Step-by-step explanation:
We have to subtract the two numbers given in scientific notation.
First number is [tex]3.4\times 10^{7}[/tex]
And the second number is [tex]1.2\times 10^{7}[/tex]
By subtracting second number from the first,
[tex](3.4\times 10^{7})-(1.2\times 10^{7})[/tex]
Take out the common term [tex]10^{7}[/tex] and then subtract the coefficients,
= [tex](3.4 - 1.2)\times 10^{7}[/tex]
= [tex]2.2\times 10^{7}[/tex]
Therefore, [tex]2.2\times 10^{7}[/tex] will be the answer.