can[x+2+3can(2x-5)]+can[x-2-can(2x-5)]=2can2
2can(2x+3y)+can(5-xy)=7
va 3can(5-x-y)-can(2x+y-3=1
BAI 1 TINH GIA TRI CUA BTHUC
A=3PHAN 1+CAN 3 -2PHAN 1-CAN 3
B=CAN 10-CAN 5 PHAN CAN 2-1 -3CAN 5 +5PHAN CAN 5+3 +2 PHAN CAN 2
BAI 2 GIAI PT
a)CAN 49-28X+4X MU 2 -5=0
b)1PHAN 2 CAN X-2 -4 CAN 4X -8 PHAN 9 +CAN 9X+18 -5=0
MOI NGUOI GIUP MINH VS MINH CAN LUON BAY GIO
CAM ON
Tim tat ca cac so thuc bac x thoa man
a)(2x-1)^2+(x-1)^3=3x+6
b) x+1= can bac x+3 ( ko viet dc can bac hi hi)
c)2x^2+1=5 . can bac x^2+1-4
Tim tat ca cac so thuc bac x thoa man
a)(2x-1)^2+(x-1)^3=3x+6
b) x+1= can bac x+3 ( ko viet dc can bac hi hi)
c)2x^2+1=5 . can bac x^2+1-4
Tim tat ca cac so thuc bac x thoa man
a)(2x-1)^2+(x-1)^3=3x+6
b) x+1= can bac x+3 ( ko viet dc can bac hi hi)
c)2x^2+1=5 . can bac x^2+1-4
giai phuong trinh x+1+can bac hai cua x2+4x+1=3can bac hai cua x
thế này đúng ko bạn ?
\(x+1+\sqrt{x^2+4x+1}=3\sqrt{x}\)
Bài 1 Thực hiện phép tính
a) (x-1)(x-2)(x-3)
b) (x^2 +x+1)(x^2-1)(x^2-x+1)
c) (2x-5)(4-3x)-(3x+11)(5-2x)-15(2x-5)
d)(x^2-2x+3)(3x-5)-(x^2+x-1)(2x+7)
mk dag can gấp nhá nhanh lên cảm ơn
a, (x-1).(x-2).(x-3)
= (x2 - 2x - x + 2) . (x-3)
= (x2 - 3x + 2). (x-3)4
= x3 - 3x2 - 3x2 + 9x + 2x -6
= x3 - 6x2 + 11x -6
b) (x2 +x+1)(x2-1)(x2-x+1)
= (x4 - x2 + x3 - x+ x2 -1) . (x2 - x +1)
= (x4 + x3 -x -1) . (x2 - x +1)
= x6 - x5 + x4 + x5 - x4 + x3 - x2 + x -1
= x6 + x3 - x2 + x - 1
c) (2x-5)(4-3x)-(3x+11)(5-2x)-15(2x-5)
= (8x - 6x2 - 20 + 15x) - (15x-6x+55-22x) - 30x + 75
= 8x - 6x2 - 20 + 15x - 15x+6x-55+22x - 30x+75
= 6x-6x2 +55
d)(x2-2x+3)(3x-5)-(x2+x-1)(2x+7)
làm tương tự phần C
lưu ý trước dấu ngoặc là dấu trừ, khi phá ngoặc ra phải đổi dấu
phan tich ;can (x+10x+21)=3can(x+3) + 2can(x+7)-6
Sửa đè \(\sqrt{x^2+10x+21}=3\sqrt{x+3}+2\sqrt{x+7}-6\)
Đk:\(x\ge-3\)
\(pt\Leftrightarrow\sqrt{\left(x+3\right)\left(x+7\right)}=3\sqrt{x+3}+2\sqrt{x+7}-6\)
Đặt \(\hept{\begin{cases}\sqrt{x+3}=a\\\sqrt{x+7}=b\end{cases}\left(a,b>0\right)}\) thì
\(\Leftrightarrow ab=3a+2b-6\)
\(\Leftrightarrow\left(a-2\right)\left(b-3\right)=0\Rightarrow\orbr{\begin{cases}a=2\\b=3\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}\sqrt{x+3}=2\\\sqrt{x+7}=3\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=1\\x=2\end{cases}}\) (thỏa)
tim x de 3can x tren can x cong 1