7( x - 5 ) - 5( 7x - 2 ) + 2( 5x - 7 ) = ( x - 2 )( x + 4 )
<=> 7x - 35 - 35x + 10 + 10x - 14 = x2 + 2x - 8
<=> -18x - 39 = x2 + 2x - 8
<=> x2 + 2x - 8 + 18x + 39 = 0
<=> x2 + 20x + 31 = 0
<=> x2 + 20x + 100 - 69 = 0
<=> ( x2 + 20x + 10 ) = 69
<=> ( x + 10 )2 = ( ±√69 )2
<=> x + 10 = √69 hoặc x + 10 = -√69
<=> x = √69 - 10 hoặc x = -√69 - 10
tim x:
7(2x-5)-5(7x-2)+2(5x-7)=(x-2)-(x+4)
x=?
7(2x-5)-5(7x-2)+2(5x-7)=(x-2)-(x-4)
Thu gọn biểu thức a)x^2-4x(3x-4)+7x-5 b)7x(x^2-5)-3x^2y(xy-6y^2) c)(5x+4)(2x-7) d)4x(2x-3)-5x(x-2)+x^2(3-x)
7(2x-5)-5(7x-2)+2(5x-7) = (x+2)-(x+4) tim x nhe ai giai giup minh vs
a,4x-10=0 b, 7-3x=9-x c, 2x-(3-5x) = 4(x+3)
d, 5-(6-x)=4(3-2x) e, 4(x+3)=-7x+17 f, 5(x-3) - 4=2(x-1)+7
g, 5(x-3)-4=2(x-1)+7 h,4(3x-2)-3(x-4)=7x+20
a,(x+3)(x^2-3x+9)-(x-3)(x^2+3x+9)
b,(x-5)(x^2+5x+25)-(x+5)(x^2-5x+25)
c,(x-4)(x^2+4x+16)-(x+4)(x^2-4x+18)
d,(x-2)(x^2+7x+49)-(x-7)(x^2-7x+49)
các bạn giúp mik bài này vs
5) (4x-5).(x+2)-(x+5).(x-3)-3x^2-x
6) (x-3).(x+7)-(2x-1).(x+2)+x.(x-1)
7) (7x-3).(2x+1)-(5x-2).(x+4)-9x^2+17x
8) -2.(x-7).(x+3)+(5x-1).(x+4)-3x^2-27x
9) (6x-5).(x+8)-(3x-1).(2x+3)-9.(4x-3)
10) (8x-1).(x+7)-(x-2).(8x+5)-11.(6x+1).
a) 2x2 + 2x(5 - x)=12 d) 2(x + 5) - x2 - 5x = 0 g) (3x + 1)2 - (x+1) = 0
b) (5 - 2x)2 - 16 = 0 e) (2x - 1)2 - 4(x + 7)(x - 7) = 0 h) x2 + 7x - 8 = 0
c) 3x2 - 3x(x-2) = 36 f) (x + 4)2 - (x + 1)(x - 1) = 16 i) -2x2 +13x -15 = 0
mik cần gấp, cảm ơn mọi người.
