rut gon (a+b)^3+(b+C)^3+(c+a)^3-3(a+b)(b+c)(c+a)
Cho cac so nguyen duong a,b,c,x,y,z
1, Biet 1/a = 3/b + c = 5/c + a. Hay rut gon phan so A = a/2b - c
2. Biet a/b = 2b/cc = 4c/a. Hay rut gon phan so B = ab + bc + ca/a2 + b + c2
3. Biet x/a = y/b =z/c. Hay rut gon phan so C = x*y*z*(b+c)*(c+a)*(a+b)/a*b*c(y+z)*(z+x)*(x+y)
4. Biet ab/a + 2b = 2/5; bc/b + 2c = 3/4; ca/c +2a = 3/5. Hay rut gon phan so D = abc/ab+bc+ca
5. Biet 3/a -4b = 5c. Hay rut gon phan so E = 3bc + ab - 4ac/6bc - 8ac -ab
Giup minh nhe! Ai lam duoc va dung cho tick.
Thanks cac ban
xin lỗi tớ ấn nhầm chỗ M=7 tớ làm lại rồi đó
ban tra loi het cac cau hoi phia tren kia ho minh dc ko?
Cho cac so nguyen duong a,b,c,x,y,z
1, Biet 1/a = 3/b + c = 5/c + a. Hay rut gon phan so A = a/2b - c
2. Biet a/b = 2b/cc = 4c/a. Hay rut gon phan so B = ab + bc + ca/a2 + b + c2
3. Biet x/a = y/b =z/c. Hay rut gon phan so C = x*y*z*(b+c)*(c+a)*(a+b)/a*b*c(y+z)*(z+x)*(x+y)
4. Biet ab/a + 2b = 2/5; bc/b + 2c = 3/4; ca/c +2a = 3/5. Hay rut gon phan so D = abc/ab+bc+ca
5. Biet 3/a -4b = 5c. Hay rut gon phan so E = 3bc + ab - 4ac/6bc - 8ac -ab
Giup minh nhe! Ai lam duoc va dung cho tick.
Thanks cac ban
rut gon
M= (a-b)^3 + (b-c)^3 + (c-a)^3 /(a-b)(b-c)(c-a)
\(M=\dfrac{\left(a-b+b-c\right)^3-3\left(a-b\right)\left(b-c\right)\left(a-b+b-c\right)+\left(c-a\right)^3}{\left(a-b\right)\left(b-c\right)\left(c-a\right)}\)
\(=\dfrac{-3\left(a-b\right)\left(b-c\right)\left(a-c\right)}{\left(a-b\right)\left(b-c\right)\left(c-a\right)}=-3\)
rut gon bieu thuc \(\left(a+b+c\right)^3-\left(b+c-a\right)^3-\left(a+c-b\right)^3-\left(a+b-c\right)^3\)
cho a+b+c=0. Rut gon M= a^3+b^3+c(a^2+b^2)-abc
a+b+c=0
=>a+b=-c
M= a3+b3+c(a2+b2)-abc
=(a+b)(a2-ab+b2)+a2c+b2c-abc
=-c(a2-ab+b2)+a2c+b2c-abc
=-c(a2-ab+b2-a2-b2+ab)
=-c(0) =0
Không đúng chỗ nào cứ nói ;)
Ta co : a+b+c=0
Hay : a+b=-c
Ta lai co : a3+b3+c(a2+b2)-abc
=(a3+b3)+c(a2+b2)-abc
=(a+b)(a2-ab+b2)+a2c+b2c-abc
=(-c)[(a2-ab+b2)+a2c+b2c-abc)
=0
rut gon \(\left(a+b\right)^3+\left(b+c\right)^3+\left(c+a\right)^3-3\left(a+b\right)\left(b+c\right)\left(c+a\right)\)
rut gon
\(C=\left(a+b+c\right)^3+\left(a-b-c\right)^3+\left(b-c-a\right)^3+\left(c-a-b\right)^3\)
Cho cac so nguyen duong a,b,c,x,y,z
1, Biet 1/a = 3/b + c = 5/c + a. Hay rut gon phan so A = a/2b - c
2. Biet a/b = 2b/cc = 4c/a. Hay rut gon phan so B = ab + bc + ca/a2 + b + c2
3. Biet x/a = y/b =z/c. Hay rut gon phan so C = x*y*z*(b+c)*(c+a)*(a+b)/a*b*c(y+z)*(z+x)*(x+y)
4. Biet ab/a + 2b = 2/5; bc/b + 2c = 3/4; ca/c +2a = 3/5. Hay rut gon phan so D = abc/ab+bc+ca
5. Biet 3/a -4b = 5c. Hay rut gon phan so E = 3bc + ab - 4ac/6bc - 8ac -ab
Giup minh nhe! Ai lam duoc va dung cho tick.
Thanks cac ban
Cac ban tra loi giup minh di, minh se cho nhieu k!
Please.....!
rut gon A=\(\frac{\left(a+b+c\right)^5-a^5-b^5-c^5}{\left(a+b+c\right)^3-a^3-b^3-c^3}\)iup minh voi di may ban