The scale factor used is .5 because 7, 8, and 10 multiplied by .5 will equal 3.5, 4, and 5.
The answer is 8! Hope that helps! Please give brainliest hehe
Multiply the coefficients and the powers of 10 with each other:

The numeric part simply yields

As for the powers of 10, you have to add the exponents, using the rule

So, we have

So, the final answer is
