Answer:
[tex]\sf 4.9 \times 10^{11}[/tex]
Step-by-step explanation:
Given expression: [tex]\sf (7 \times 10^5)^2[/tex]
Apply exponent rule [tex]\sf (ab)^2=a^2 \cdot b^2[/tex] :
[tex]\sf \implies 7^2 \times (10^5)^2[/tex]
[tex]\sf \implies 49 \times (10^5)^2[/tex]
Apply exponent rule [tex]\sf (a^b)^c=a^{bc}[/tex] :
[tex]\sf \implies 49 \times 10^{5 \cdot 2}[/tex]
[tex]\sf \implies 49 \times 10^{10}[/tex]
Scientific notation: [tex]\sf a \times 10^n[/tex]
where [tex]\sf 1\leq a < 10[/tex] and n is an integer
We can write 49 as [tex]\sf 4.9 \times 10=4.9 \times 10^1[/tex]
[tex]\sf \implies 4.9 \times 10^1\times 10^{10}[/tex]
Apply exponent rule [tex]\sf a^ba^c=a^{b+c}[/tex]
[tex]\sf \implies 4.9 \times 10^{11}[/tex]