[Toán 8] Giải phương trình

T

tiendat_no.1

linhtinh98 said:
a. 3x2 - 2m2m1m3m4= x (3x+ 2) - 5
\Leftrightarrow3x2-22=x2+2x-5
\Leftrightarrow3x2-4=3x2+2x-5
\Leftrightarrow3x2-3x2-2x=-5+3
\Leftrightarrow-2x=-1
\Leftrightarrow X=1/2
b.3x2 + 4x + 2 = x( 2x+3 )
\Leftrightarrow 3x2+4x-2-2x2-3x=0
\LeftrightarrowX2+x-2=0
\LeftrightarrowX2-x+2x-2=0
\Leftrightarrow (x2-x) (2x-2)=0
\LeftrightarrowX (x-1)+2(x-1)=0
\Leftrightarrow(x-1) (x+2)=0
\Leftrightarrowx-1=0 \Leftrightarrow x=1
x+2=0 x=-2
c.5x2 + 5x = 4x (x- 1)-2
tuong tu !!!!!!!!!!!
##d.x2 + x -12 = 0
\LeftrightarrowX2-3x+4x-12=0
\Leftrightarrow(x2-3x) +(4x-12)=0
\LeftrightarrowX (x-3)+4(x-3)=0
\Leftrightarrow(x-4) (x-3) =0
\Leftrightarrowx-3=0 \Leftrightarrow x=3
x+4=0 x =-4
e.x5+ x + 1 = 0
tuong tu bai d………….!!!!!
Bấm để xem đầy đủ nội dung ...

chac dung…..hì…hì.....................................!!!!!!!!!!!!!!!!!!!!
 
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