Viết các tổng sau đây thành tích:
a) ab+bd-ac-cd
b) ax+by-ay-bx
c) x2-xy-xy+y2)
d)x2+5x+6
a) 5x-5y+ax-ay b) ax+ay+bx+by c) x2+x+ax+a
d) x2y+xy2+xy2-3x-3y e) x2y+xy-x-1 f) x2+2x-2x-4
g) x2+6x-y2+9 h) x2-y2+10x+25 i) x2-8x-24y2+16
\(a,=5\left(x-y\right)+a\left(x-y\right)=\left(5+a\right)\left(x-y\right)\\ b,=a\left(x+y\right)+b\left(x+y\right)=\left(a+b\right)\left(x+y\right)\\ c,=x\left(x+1\right)+a\left(x+1\right)=\left(x+a\right)\left(x+1\right)\\ d,Sửa:x^2y+xy^2-3x-3y=xy\left(x+y\right)-3\left(x+y\right)=\left(xy-3\right)\left(x+y\right)\\ e,=xy\left(x+1\right)-\left(x+1\right)=\left(xy-1\right)\left(x+1\right)\\ f,=x^2-4=\left(x-2\right)\left(x+2\right)\\ g,=\left(x+3\right)^2-y^2=\left(x-y+3\right)\left(x+y+3\right)\\ h,=\left(x+5\right)^2-y^2=\left(x-y+5\right)\left(x+y+5\right)\\ i,=\left(x-4\right)^2-24y^2=\left(x-2\sqrt{6}y-4\right)\left(x+2\sqrt{6}y+4\right)\)
phân tích các đa thức sau thành nhân tử
a) 5x2 - 10xy + 5y2 - 20z
b) x2 - z2 + y2 - 2xy
c) a3 - ay - a2x + xy
d) x2 + 4x + 3
b: \(x^2-2xy+y^2-z^2\)
\(=\left(x-y\right)^2-z^2\)
\(=\left(x-y-z\right)\left(x-y+z\right)\)
d: \(x^2+4x+3=\left(x+3\right)\left(x+1\right)\)
=x4−2x3+2x3−4x2+4x2−8x+7x−14=x4−2x3+2x3−4x2+4x2−8x+7x−14
=(x−2)(x3+2x2+4x+7)
bài 1 phân tích các đa thức thành nhân tử
a) x2 - z2 + y2 - 2xy b) a3 - ay - a2x + xy
c) x2 - 2xy + y2 - xz + yz d) x2 - 2xy + tx - 2ty
bài 2 giải các phương trình sau
( x - 2 )2 - ( x - 3 ) ( x+ 3 ) = 6
bài 3 chứng minh rằng
a) x2 + 2x + 2 > 0 với xϵZ
b) -x2 + 4x - 5 < 0 với x ϵ Z
\(1,\\ a,=\left(x-y\right)^2-z^2=\left(x-y-z\right)\left(x-y+z\right)\\ b,=a^2\left(a-x\right)-y\left(a-x\right)=\left(a^2-y\right)\left(a-x\right)\\ c,=\left(x-y\right)^2-z\left(x-y\right)=\left(x-y\right)\left(x-y-z\right)\\ d,=x\left(x-2y\right)+t\left(x-2y\right)=\left(x+t\right)\left(x-2y\right)\\ 2,\\ \Rightarrow x^2-4x+4-x^2+9=6\\ \Rightarrow-4x=-7\Rightarrow x=\dfrac{7}{4}\\ 3,\\ a,x^2+2x+2=\left(x+1\right)^2+1\ge1>0\\ b,-x^2+4x-5=-\left(x-2\right)^2-1\le-1< 0\)
Viết dưới dạng tích các tổng sau;
1,ab+ac
2,ab-ac+ab
3,ax-bx-cx+dx
4,a(b+c)-d(b+c)
5,ac-ab+bc-bd
6,ax+by+bx+ay
Rút gọn biểu thức
a. 2x+2y/a2+2ab+b2 . ax-ay+bx-by/2x2-2y2
b. a+b-c/a2+2ab+b2-c2 . a2+2ab+b2+ac+bc/a2-b2
c.x3+1/x2+2x+1 . x2-1/2x2-2x+2
d. x8-1/x+1 . 1/ (x2+1) (x4+1)
e. x-y/xy+y2 - 3x+y/x2-xy . y-x/x+y
a2 c2... là em viết số mũ đó ạ. anh chị giúp em giải mấy bài này nha
\(=\dfrac{2\left(x+y\right)}{\left(a+b\right)^2}.\dfrac{a\left(x-y\right)+b\left(x-y\right)}{2\left(x^2-y^2\right)}\)
\(=\dfrac{2\left(x+y\right)}{\left(a+b\right)^2}.\dfrac{\left(x-y\right)\left(a+b\right)}{2\left(x-y\right)\left(x+y\right)}\)
\(=\dfrac{1}{a+b}\)
\(=\dfrac{a+b-c}{\left(a+b\right)^2-c^2}.\dfrac{\left(a+b\right)^2+c\left(a+b\right)}{\left(a-b\right)\left(a+b\right)}\)
\(=\dfrac{a+b-c}{\left(a+b-c\right)\left(a+b+c\right)}.\dfrac{\left(a+b\right)\left(a+b+c\right)}{\left(a-b\right)\left(a+b\right)}\)
\(=\dfrac{1}{a-b}\)
\(c,\dfrac{x^3+1}{x^2+2x+1}.\dfrac{x^2-1}{2x^2-2x+2}\)
\(=\dfrac{\left(x+1\right)\left(x^2-x+1\right)}{\left(x+1\right)^2}.\dfrac{\left(x-1\right)\left(x+1\right)}{2\left(x^2-x+1\right)}\) \(=\dfrac{x-1}{2}\) \(d,\dfrac{x^8-1}{x+1}.\dfrac{1}{\left(x^2+1\right)\left(x^4+1\right)}\) \(=\dfrac{\left(x^4\right)^2-1}{x+1}.\dfrac{1}{\left(x^2+1\right)\left(x^4+1\right)}\) \(=\dfrac{\left(x^4-1\right)\left(x^4+1\right)}{x+1}.\dfrac{1}{\left(x^2+1\right)\left(x^4+1\right)}\) \(=\dfrac{\left(x^2+1\right)\left(x^2-1\right)}{x+1}.\dfrac{1}{x^2+1}\) \(=\dfrac{\left(x-1\right)\left(x+1\right)}{x+1}\) \(=x-1\) \(e,\dfrac{x-y}{xy+y^2}-\dfrac{3x+y}{x^2-xy}.\dfrac{y-x}{x+y}\) \(=\dfrac{x-y}{y\left(x+y\right)}-\dfrac{3x+y}{x\left(x-y\right)}.\dfrac{-\left(x-y\right)}{x+y}\) \(=\dfrac{x-y}{y\left(x+y\right)}-\dfrac{3x+y}{x}.\dfrac{-1}{x+y}\) \(=\dfrac{x-y}{y\left(x+y\right)}-\dfrac{-3x-y}{x\left(x+y\right)}\) \(=\dfrac{x\left(x-y\right)+y\left(3x+y\right)}{xy\left(x+y\right)}\) \(=\dfrac{x^2-xy+3xy+y^2}{xy\left(x+y\right)}\) \(=\dfrac{x^2+2xy+y^2}{xy\left(x+y\right)}\) \(=\dfrac{\left(x+y\right)^2}{xy\left(x+y\right)}=\dfrac{x+y}{xy}\)Viết dưới dạng tích các tổng sau : ab+ac ; ab -ac+ad; ax -bx-cx+dx; a(b+c) - d (b+c); ac-ad+bc-bd; ax+by+bx+ay
ab + ac = a(b + c)
ab - ac + ad = a(b - c + d)
ax - bx - cx + dx
=x(a - b - c + d)
ab+ac=a(b+c)
ab-ac+ad=a(b-c+d)
ax-bx-cx+dx=x(a-b-c+d)
Phân tích các đa thức sau thành nhân tử:
a) x 2 + 6x + 8; b) 2 x 2 + 14x +12;
c) 9 x 2 + 24x +15; d) 6 x 2 -xy-7 y 2 .
a) (x + 2)(x + 4). b) 2(x + 6)(x + l).
c) 3(3x + 5)(x + l). d) (6x -7y)(x + y).
Viết dưới dạng tích các tổng sau
1) ab + ac
2) ab-ac+ad
3) ax-bx-cx+dx
4) a(b+c)-d(b+c)
5) ac-ad+bc-bd
6) ax+by+bx+ay
1) ab + ac = a(b + c)
2) ab - ac + ad = a(b - c + d)
3) ax - bx - cx + dx = x(a - b - c + d)
4) a(b + c) - d(b + c) = (b + c)(a - d)
5) ac - ad + bc - bd = a(c - d) + b(c - d) = (c - d)(a + b)
6) ax + by + bx + ay = (ax + ay) + (bx + by) = a(x + y) + b(x + y) = (x + y)(a + b)
ab + ac = a ( b + c )
ab - ac + ad = a ( b - c + d )
ax - bx - cx + dx = x ( a - b - c + d )
Viết dưới dạng tích các tổng sau:
1/ ab + ac
2/ ab - ac +ad
3/ ax - bx - cx +dx
4/ a(b+c) - d(b+c)
5/ ac - ad + bc- bd
6/ ax + by + bx + ay
1/ab+ac=a(b+c)
2/ab-ac+ad=a(b-c)+ad=a(b-c+d)
3/ax-bx-cx+dx=x(a-b-c)+xd=x(a-b-c+d)
4/a(b+c)-d(b+c)=(ab+ac)-(bd+cd)=b(a+d)-c(a+d)=a+d(b+c)
5/ac-ad+bc-bd=a(c-d)+b(c-d)=c-d(a+b)
6/ax+by+bx+ay=a(x+y)+b(x+y)=x+y(a+b)
1/ ab+ac=a(b+c)
2/ab-ac+ad=a(b-c+d)
3/ax-bx-cx+dx=x(a-b-c+d)
4/a(b+c)-d(b+c)=(b+c)(a-d)
5/ac-ad+bc-bd=a(c-d)+b(c-d)=(c-d)(a+b)
6/ax+by+bx+ay=a(x+y)+b(y+x)=(y+x)(a+b)
\(1,ab+ac\)
\(=a\left(b+c\right)\)
\(2,ab-ac+ad\)
\(=a\left(b-c+d\right)\)
\(3,ax-bx-cx+dx\)
\(=x\left(a-b-c+d\right)\)
\(4,a\left(b+c\right)-d\left(b+c\right)\)
\(=\left(b+c\right)\left(a-d\right)\)
\(5,ac-ad+bc-bd\)
\(=a\left(c-d\right)+b\left(c-d\right)\)
\(=\left(a+b\right)\left(c-d\right)\)
\(6,ax+by+bx+ay\)
\(=\left(ax+bx\right)+\left(by+ay\right)\)
\(=x\left(a+b\right)+y\left(a+b\right)\)
\(=\left(x+y\right)\left(a+b\right)\)