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otez555 [7]
2 years ago
12

Find the sum of the digits 10^15−1.

Mathematics
2 answers:
Shtirlitz [24]2 years ago
8 0

Answer:

135

Step-by-step explanation:

10^15 = 1 000 000 000 000 000

10^15 - 1 = 999 999 999 999 999

There are 15 nines

15*9 = 135

Alchen [17]2 years ago
4 0

Answer:

149

Step-by-step explanation:

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Step 1. We are going to begin with standard form a quadratic equation: ax^2+bx+c=0

Step 2.  Divide both sides of the equation by a:
\frac{ax^2+bx+c}{a} = \frac{0}{a}
\frac{ax^2}{a} + \frac{bx}{c} + \frac{c}{a} =0
x^{2} + \frac{b}{a} x+ \frac{c}{a} =0

Step 3. Subtract \frac{c}{a} from both sides of the equation:
x^{2} + \frac{b}{a} x+ \frac{c}{a}- \frac{c}{a}  =0 - \frac{c}{a}
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Step 4. Complete the square of the left hand side by adding ( \frac{b}{2a} )^2 to both sides:
x^{2} + \frac{b}{a} x+( \frac{b}{2a} )^2=- \frac{c}{a} +( \frac{b}{2a} )^2
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Step 5. Take square root to both sides of the equation:
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Step-by-step explanation:

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