Question 278380
using this formula, solve; A^3+B^3=(A+B)(A²-AB+B²) or A^3-B^3=(A-B)(A²+AB+B²) 
1. 27y³-1 = (3y^3-1^3) = (3y-1)(9y^2+3y+1)
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 in this problem, contain polynomials in several variables. Factor 
each polynomial completely & check using multiplication. 
2. 16a³b²-4ab² = 4ab^2(4a^2-1) = 4ab^2(2a-1)(2a+1)
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Use factoring to solve each quadraic equation. Check by substitution
or by graphing utility & identifying x-intercepts. 
3.y(y+9)=4(2y+5)
y^2+9y = 8y+20
y^2+y-20 = 0
(y+5)(y-4)=0
 y = -5 or y = 4
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Note: (4,-5) is not the proper way to express the answer.
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Cheers,
Stan H.