dai so 8

C

congchuaanhsang

a,$3x^2$-5x-2=($3x^2$+x)-(6x+2)
=x(3x+1)-2(3x+1)=(x-2)(3x+1)
b,$12x^2$+7x-12=($12x^2$+16x)-(9x+12)
=4x(3x+4)-3(3x+4)=(4x-3)(3x+4)
 
P

pro0o

a) $3x^2-5x-2$

$= 3x^2 + x - 6x - 2 = (3x^2 - 6x) + x-2 = 3x(x - 2) + x-2 = (3x +1)(x-2)$


b)$12x^2+7x-12$
$= 12x^2 + 16x - 9x - 12 = 4x(3x + 4) - 3(3x + 4) = (4x - 3)(3x + 4)$
 
P

pandahieu


We have :
a,$$3x^2-5x-2$$
$$=(3x^2+x)-(6x+2)$$
$$=x(3x+1)-2(3x+1)$$
$$=\boxed{(x-2)(3x+1)}$$
b,
$$12x^2$+7x-12$$
$$=(12x^2+16x)-(9x+12)$$
$$=4x(3x+4)-3(3x+4)$$
$$=\boxed{(4x-3)(3x+4)}$$
 
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