Question

Please answer the questions below

Answer 1

Answer:

Step-by-step explanation:

4.(i)8-27b³-343c³-126bc

  =(2)³+(-3b)³+(-7c)³-3(2)(-3b)(-7c)

  =(2-3b-7c)[(2)²+(-3b)²+(-7c)²-(2)(-3b)-(-3b)(-7c)-(-7c)(2)]

  =(2-3b-7c)(4+9b²+49c²+6b-21bc+14c)

(ii)x²-y²+6y-9

=(x)²-[y²+9-6y]

=(x)²-[(y)²+(3)²-2(y)(3)]

=(x)²-(y-3)²

=[(x)+(y-3)][(x)-(y-3)]

=(x+y-3)(x-y+3)

(iii)125a³+b³+64c³-60abc

 =(5a)³+(b)³+(4c)³-3(5a)(b)(4c)

 =(5a+b+4c)[(5a)²+(b)²+(4c)²-(5a)(b)-(b)(4c)-(4c)(5a)]

 =(5a+b+4c)(25a²+b²+16c²-5ab-4bc-20ca)

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