The sum of 4 x 10−6 and 2.2 x 10−5 is 6. 2 × 10 ^ -5. Option D
Index is simply the power or exponent which is raised to a number or a variable.
From the information given, we have;
4 x 10^−6 and 2.2 x 10^−5
To find the sum, the two index forms must have the same exponent or power
4. 0 × 10 ^ -5 and 2.2 x 10−5
This is written as ;
4. 0 × 10^-5 + 2. 2 × 10 ^ -5
Using the law of indices, add the two values and take the power
4. 0 + 2. 2 × 10 ^-5
6. 2 × 10 ^ -5
Thus, the sum of 4 x 10−6 and 2.2 x 10−5 is 6. 2 × 10 ^ -5. Option D
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