Answer:
[tex]=8750x^2\\[/tex]
Step-by-step explanation:
[tex]\mathrm{Apply\:exponent\:rule}:\quad \:a^b\cdot \:a^c=a^{b+c}\\=2.5x\cdot \:3.5x\cdot \:10^{10-7}[/tex]
...
[tex]\mathrm{Multiply\:the\:numbers:}\:2.5\cdot \:3.5=8.75\\=10^3\cdot \:8.75x^2[/tex]
[tex]\mathrm{Multiply\:the\:numbers:}\:8.75\cdot \:1000=8750\[[/tex]
=8750x^2