✔ 最佳答案
factorize each of the following:
1. (2x-3)^2+24x-4x-6
= (2x-3)^2 + 20x - 6
= 4x^2 - 12x + 9 + 20x - 6
= 4x^2 + 8x + 3
= (2x + 1)(2x + 3)
2.(4x-3y)^2+(3y+4x)(3y-4x)
= (4x-3y)^2 - (3y+4x)(4x-3y)
= (4x-3y)(4x-3y) - (3y+4x)(4x-3y)
= (4x-3y)( 4x-3y - (3y+4x) )
= (4x-3y)( - 6y)
= 6y(3y - 4x)
solve the following exponential equations:
1. 5^(4x+3)-15(5^(4x)) = 22 (over) 5
(5^3) * (5^4x) - 15(5^4x) = 22/5
(5 ^ 4x)(5^3 - 15) = 22/5
5 ^ 4x = (22/5) / (125 - 15)
5 ^ 4x = 1/25
5 ^ 4x = 1 / 5^2
5 ^ 4x = 5 ^ - 2
4x = - 2
x = - 1/2
( negative x over 3 minus y) times (negative 2x plus 6y)
(- x / (3 - y) ) * (- 2x + 6y)
= [x / (y - 3) ] (6y - 2x)
= (6xy - 2x^2) / (y - 3)
= 6xy / (y - 3) - (2x^2) / (y - 3)
2009-12-06 00:41:26 補充：
對不起,理解錯了題目( negative x over 3 minus y) times (negative 2x plus 6y)
應是 : [(- x/3) - y ] * (- 2x + 6y)
= (-1/3)(x + 3y) * (-2)(x - 3y)
= (-1/3)(-2)(x + 3y)(x - 3y)
= (2/3)(x^2 - 9y^2)
= (2x^2)/3 - 6y^2
2009-12-06 00:41:47 補充：
對不起,理解錯了題目( negative x over 3 minus y) times (negative 2x plus 6y)
應是 : [(- x/3) - y ] * (- 2x + 6y)
= (-1/3)(x + 3y) * (-2)(x - 3y)
= (-1/3)(-2)(x + 3y)(x - 3y)
= (2/3)(x^2 - 9y^2)
= (2x^2)/3 - 6y^2
