Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1) x2 + 10x + 26 + y2 + 2y
= (x2 + 10x + 25) + (y2 + 2y + 1)
= (x2 + 5x + 5x + 25) + (y2 + y + y + 1)
= x(x + 5) + 5(x + 5) + y(y + 1) + (y + 1)
= (x + 5)2 + (y + 1)2
2) z2 - 6z + 13 + t2 + 4t
= (z2 - 6z + 9) + (t2 + 4t + 4)
= (z2 - 3z - 3z + 9) + (t2 + 2t + 2t + 4)
= z(z - 3) - 3(z - 3) + t(t + 2) + 2(t + 2)
= (z - 3)2 + (t + 2)2
3) x2 - 2xy + 2y2 + 2y + 1
(x2 - 2xy + y2) + (y2 + 2y + 1)
= (x - xy - xy + y2) + (y2 + y + y +1)
= x(x - y) - y(x - y) + y(y + 1) + (y + 1)
= (x - y)2 + (y + 1)2
Bài 1:
a) \(x^2+10x+26+y^2+2y=(x^2+10x+25)+(y^2+2y+1)\)
..................................................= \(\left(x+5\right)^2+\left(y+1\right)^2\)
b) \(z^2-6z+5-t^2-4t=(z^2-6t+9)-(t^2+4t+4)\)
............................................= \(\left(z-3\right)^2-\left(t+2\right)^2\)
c) \(x^2-2xy+2y^2+2y+1=(x^2-2xy+y^2)+(y^2+2y+1)\)
..................................................= \(\left(x-y\right)^2+\left(y+1\right)^2\)
d) \(4x^2-12x-y^2+2y+8=\left(4x^2-12x+9\right)-\left(y^2-2y+1\right)\)
.................................................= \(\left(2x-3\right)^2-\left(y-1\right)^2\)
Bài 2:
a) \(\left(x+y+4\right)\left(x+y-4\right)=\left(x+y\right)^2-16\)
b) \(\left(x-y+6\right)\left(x+y-6\right)=x^2-\left(y-6\right)^2\)
c) \(\left(y+2z-3\right)\left(y-2z+3\right)=y^2-\left(2z-3\right)^2\)
d) \(\left(x+2y+3z\right)\left(2y+3z-x\right)=\left(2y+3z\right)^2-x^2\)
a/ \(\left(3x^2-2xy+y^2\right)+\left(x^2-xy+2y^2\right)-\left(4x^2-y^2\right)\)
\(=3x^2-2xy+y^2+x^2-xy+2y^2-4x^2+y^2\)
\(=-3xy+4y^2\)
b/ \(\left(x^2-y^2+2xy\right)-\left(x^2+xy+2y^2\right)+\left(4xy-1\right)\)
\(=x^2-y^2+2xy-x^2-xy-2y^2+4xy-1\)
\(=-3y^2+5xy-1\)
a) \(\left(3x^2-2xy+y^2\right)+\left(x^2-xy+2y^2\right)-\left(4x^2-y^2\right)\)
\(=3x^2-2xy+y^2+x^2-xy+2y^2-4x^2+y^2\)
\(=4y^2-3xy\)
b) \(\left(x^2-y^2+2xy\right)-\left(x^2+xy+2y^2\right)+\left(4xy-1\right)\)
\(=x^2-y^2+2xy-x^2-xy-2y^2+4xy-1\)
\(=-3y^2+5xy-1\)
(x + 2y)2 - 16
= (x + 2y)2 - 42
= (x + 2y - 4).(x + 2y + 4)
(x - 2y)2 - 4.(x - 2y) + 4
= (x - 2y)2 - 2.(x - 2y).2 + 22
= (x - 2y - 2)2
(a2 + 1)2 - 6.(a2 + 1) + 9
= (a2 + 1)2 - 2.(a2 + 1).3 + 32
= (a2 + 1 - 3)2
= (a2 - 2)2
(x + y)2 + (x + y).x + 1/4.x2
= (x + y)2 + 2.(x + y).1/2.x + (1/2.x)2
= (x + y + 1/2.x)2
= (3/2.x + y)2
16x4 - 9x2
= (4x2)2 - (3x)2
= (4x2 - 3x).(4x2 + 3x)
a2 - b4
= a2 - (b2)2
= (a - b2).(a + b2)
Bạn ơi câu b) bạn sai rồi, số nào nhân vs 0 đều = 0 nên đâu cần phải thay nữa đâu
a) Đa thức M = x2 - 2xy + 5x2 - 1 = 6x2 - 2xy - 1 có bậc 2.
Đa thức N = x2y2 - y2 + 5x2 - 3x2y + 5 có bậc 4.
b) N + M = x2y2 – y2 + 11x2 – 3x2y + 4 – 2xy
\(x^2+10x+26+y^2+2y=\left(x^2+10x+25\right)+\left(y^2+2y+1\right)=\left(x+5\right)^2+\left(y+1\right)^2\)
\(z^2-6z+5-t^2-4=\left(z^2-6z+9\right)-\left(t^2+8\right)=\left(z-3\right)^2-\left(t^2+8\right)\)
\(x^2-2xy+2y^2+2y+1=\left(x^2-2xy+y^2\right)+\left(y^2+2y+1\right)=\left(x-y\right)^2+\left(y+1\right)^2\)
\(4x^2-12x-y^2+2y+1=\left(4x^2-12x+9\right)-\left(y^2-2y+1\right)-7=\left(2x-3\right)^2-\left(y-1\right)^2-7\)
Chúc bạn học giỏi
Kết bạn với mình nha