Answers

1. Answer:

   3.2838 × 10^7

   Step-by-step explanation

   (4.21)(7.8)=3.2838 × 10^1

   in order to get the exponent, you add the previous two together

   -9+15=7

   = 3.2838 × 10^7

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2. The simplification of the number expression (4.21×10⁻⁹)(7.8×10¹⁵) is 3.2838×10⁷ after writing in the scientific notation.

   What is an arithmetic operation?

   It is defined as the operation in which we do the addition of numbers, subtraction, multiplication, and division. It has basic four operators that is +, -, ×, and ÷.

   It is given that:

   The number expression is:

   = (4.21×10⁻⁹)(7.8×10¹⁵)

   The expression can be defined as the combination of constants and variables with mathematical operators.

   = (4.21)(7.8) = 3.2838×10×10⁶

   After applying the property of integer exponent:

   = 3.2838×10⁷

   Thus, the simplification of the number expression (4.21×10⁻⁹)(7.8×10¹⁵) is 3.2838×10⁷ after writing in the scientific notation.

   Learn more about the arithmetic operation here:

   brainly.com/question/20595275

   #SPJ5

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