$Use\\a^2-b^2=(a-b)(a+b)\\(ab)^n=a^nb^n\\(\sqrt{a})^2=a\ for\ a\geq0\\------------------------------\\A)\ 64x^2-49y^2=8^2x^2-7^2y^2=(8x)^2-(7y)^2=(8x-7y)(8x+7y)\\\\B)\ 20x^2-45y^2=(\sqrt{20})^2x^2-(\sqrt{45})^2y^2=(*)\\\\\sqrt{20}=\sqrt{4\cdot5}=\sqrt4\cdot\sqrt5=2\sqrt5\\\sqrt{45}=\sqrt{9\cdot5}=\sqrt9\cdot\sqrt5=3\sqrt5\\\\(*)=(2\sqrt5x)^2-(3\sqrt5y)^2=(2\sqrt5x-3\sqrt5y)(3\sqrt5x+3\sqrt5y)$

$or:\\\\20x^2-45y^2=5\cdot4x^2-5\cdot9y^2=5(4x^2-9y^2)=5[(2x)^2-(3y)^2]\\\\=5(2x-3y)(2x+3y)$

3 0

3 years ago

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Explain how you could convert a rate of 18000 miles per hour to miles per second

Ulleksa [173]

You could multiply that fraction by (1 hour / 3,600 seconds) .

 (18,000 mile / 1 hour) x (1 hour / 3,600 second) =

 (18,000 x 1) / (1 x 3,600) (mile-hour) / (hour-second) =

 (18,000 / 3,600) (mile / second) = 5 mile/second

5 0

3 years ago

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