1. 27x³ - 8
2. 9x² +30x + 25
3. 4x² -23x +15
4. 9x² - 66x + 121
5. 6x² + 9x
2007-09-05 04:55:26 · 4 answers · asked by shiela_closer 1 in Science & Mathematics ➔ Mathematics
1)
using the identity, a^3 - b^3 = (a - b)(a^2 +ab +b^2)
27x^3 - 8 =
(3x)^3 - (2)^3 = (3x - 2)(9x^2 +6x + 4)
2)
9x^2 + 30x + 25 =
(3x)^2 + 2(3x)(5) + 5^2 = (3x + 5)^2
since a^2 + 2ab+ b^2 = (a + b)^2
3)
4x^2 - 23x + 15
4x^2 - 20x - 3x + 15 =
4x(x - 5) - 3(x - 5) =
(x - 5)(4x - 3)
4)
a^2 - 2ab + b^2 = (a - b)^2
9x^2 - 66x + 121 =
(3x)^2 - 2(3x)(11) + (11)^2 = (3x - 11)^2
5)
6x^2 + 9x =
3x(2x + 3)
2007-09-05 05:28:02 · answer #1 · answered by mohanrao d 7 · 0⤊ 0⤋
1) (3x)^3 - 2^3=(3x-2) (9x^2 + 4 + 6x);
2) 9x^2 + 30x + 25= (3x)^2 + 2*3x*5 + 5^2= (3x+5)^2;
3)4x^2 -23x +15= 4x^2-20x-3x +15= 4x(x-5) -3(x-5)=
(4x-3) (x-5);
4) (3x)^2 -2*3x*11 + (11)^2= (3x-11)^2;
5) 3x(2x+3);
2007-09-05 12:11:19 · answer #2 · answered by karan s 3 · 0⤊ 0⤋
1) 27x^3-8
=(3x)^3-(2)^3
=(3x-2)(9x^2+6x+4) ans
2) 9x^2+30x+25
=9x^2+15x+15x+25
=3x(3x+5)+5(3x+5)
=(3x+5)(3x+5) or (3x+5)^2 ans
3)4x^2-23x+15
=4x^2-3x-20x+15
=x(4x-3)-5(4x-3)
=(4x-3)(x-5) ans
4) 9x^^2-66x+121
=(3x)^2-2.3.11+(11)^2
=(3x-11)^2 ans
5)6x^2+9x
=3x(2x+3) ans
2007-09-05 13:00:48 · answer #3 · answered by MAHAANIM07 4 · 0⤊ 0⤋
1. (3x-2)(9x² +6x-4)
2. (3x+5)²
3. (4x-3)(x-5)
4. (3x-11)²
5. 3x(x+2)
2007-09-05 12:06:01 · answer #4 · answered by 037 G 6 · 0⤊ 0⤋