a. 10.5x10power of -5

b. 1.05x10 power of -6

c. 10.5x10 power of 5

d. 1.05x10 power of 6

a. 10.5x10power of -5

b. 1.05x10 power of -6

c. 10.5x10 power of 5

d. 1.05x10 power of 6

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(2.5 x 10^{3})(4.2 x 10^{2}) = (2.5)(4.2)(10^{3})(10^{2})

= 10.5 x 10^{5} (Multiply exponential expressions with the same base; add the exponents)

So answer c is an equivalent value but is not in scientific notation. We need to change 10.5 to 1.05. To do this we are dividing by 10, so we have to multiply the exponential portion by 10 to make up for it. Therefore, the answer in scientific notation is 1.05 x 10^{6} or answer d.

(2.5x 10^{3}) (4.2 x 10^{2})

= (2.5 x 4.2) x ( 10^{3+2} )

= 10.50 x 10^{5}

Answer is c.

## Comments

That is numerically equivalent but not in proper scientific notation.

Thanks!