Question

Simplify (2.8 x 10-9) - (6.9 x 10-8). Write the final answer in scientific notation.

-6.62 x 10-9
-6.62 x 10-8
-4.1 x 10-1
-4.1 x 101

Answer 1

• - 6.62 × 10⁻⁸

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Simplify by equalizing the exponent of each term

• 2.8 × 10⁻⁹ - 6.9 × 10⁻⁸ = Make both exponents same, - 8
• 0.28 × 10⁻⁸ - 69 × 10⁻⁸ = Move the decimal of 2.8 left by one digit, it helps to bring the exponent up from -9 to -8
• (0.28 - 6.9) × 10⁻⁸ = Factor out the exponent part
• - 6.62 × 10⁻⁸ Simplify to get final value