Find an odd natural numbers x such that LCM (x, 40) = 1400

Mathematics

1 answer:

vesna_86 [32]3 years ago

5 0

Answer:

Let x be odd such that LCM {x,40} = 1400 .

Since 1400 = 23×52×7 , then

x ∈ {5m×7n∣(m,n) ∈ {0,1,2}×{0,1}} .

By testing these values, we find that x = 175 .

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0.0000126 scientific notation

frosja888 [35]

That number in scientific notation is 1.26 x10^-5. The decimal up front has to be greater than 1, but less than 10. We move the decimal to the left to get that answer 5 times. That is what gets us 1.26 x10^-5.

8 0

3 years ago

I need help!! please

Elan Coil [88]

<h3>Answer: 40</h3>

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Explanation:

The old dimensions of the rectangle were 30 by 15.

The new dimensions are 30+x by 15+x, where x is some positive number.

The new rectangle dimensions multiply to 1000

(30+x)(15+x) = 1000

Use the FOIL rule to expand out the left side like so

(30+x)(15+x) = 1000

450+30x+15x+x^2 = 1000

450+45x+x^2 = 1000

x^2+45x+450

Then lets get everything to one side

x^2+45x+450 = 1000

x^2+45x+450-1000 = 0

x^2+45x-550 = 0

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From here we use the quadratic formula

Plug in a = 1, b = 45, and c = -550.

$x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\\\\x = \frac{-(45)\pm\sqrt{(45)^2-4(1)(-550)}}{2(1)}\\\\x = \frac{-45\pm\sqrt{4225}}{2}\\\\$

$x = \frac{-45\pm65}{2}\\\\x = \frac{-45+65}{2} \ \text{ or } \ x = \frac{-45-65}{2}\\\\x = \frac{20}{2} \ \text{ or } \ x = \frac{-110}{2}\\\\x = 10 \ \text{ or } \ x = -55\\\\$