Question 196135
1) factor 112s^2+392sf+343f^2 
7*16s^2 + 7*56sf + 7*49f^2
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7(16s^2 + 56sf + 49f^2)
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7(4s + 7f)(4s + 7f)

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2) f(x)=3x^2-15 need the x intercept 
Let y = 0 ; solve for "x"
3x^2 - 15 = 0
3(x^2 - 5) = 0
x = sqrt(5) or x = -sqrt(5)
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3) 4x(x-1)-5x(x)=3 
4x^2 - 4 - 5x^2 = 3
-x^2 = 7
x^2 = -7
x = sqrt(7)i or x = -sqrt(7)i
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4) x^1/6 * y^1/8 *z^1/3 
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x^(4/24) * y^(3/24) * z(8/24)
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(x^4 * y^3 * z*8)^(1/24)
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Cheers,
Stan H.