bỏ dấu rut gon bieuthuc
a,(a+b)-(a-b)+(a-c)-(a+c)
b,(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
rut gon bieu thuc S = a-b/a+b + b-c/b+c + c-a/c+a + (a+b)(b-c)(c-a) / (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 (a+b)^3+(b+C)^3+(c+a)^3-3(a+b)(b+c)(c+a)
Bỏ dấu ngoặc rồi thu gon :
A= ( a - b ) - ( a - b - c) - ( 2b +c - a )
A = (a - b ) - ( a - b - c) - ( 2b +c - a )
= a - b - a + b + c - 2b - c + a
= ( a - a + a) - (b - b + 2b) + ( c- c)
= a - 2b + 0
= a - 2b
A= (a - b) - (a - b - c) - (2b + c - a)
= a - b - a + b + c - 2b -c + a
= a - 2b
Bỏ dấu ngoặc rồi thu gon:
( a- b)-(a-b-c)-(2b+c-a)
( a - b ) - ( a - b - c ) - ( 2b + c - a )
= a - b - a - b - c - 2b + c - a
= a - a - a - b - b - 2b - c + c
= a - 2b
= a - b - a + b + c - 2b - c + a
= a - 2b
rut gon
M= (a-b)^3 + (b-c)^3 + (c-a)^3 /(a-b)(b-c)(c-a)
\(M=\dfrac{\left(a-b+b-c\right)^3-3\left(a-b\right)\left(b-c\right)\left(a-b+b-c\right)+\left(c-a\right)^3}{\left(a-b\right)\left(b-c\right)\left(c-a\right)}\)
\(=\dfrac{-3\left(a-b\right)\left(b-c\right)\left(a-c\right)}{\left(a-b\right)\left(b-c\right)\left(c-a\right)}=-3\)
Cho A=(-a+b-c)-(-a-b-c)
a) Rut gon A
b) Tinh A khi a=2009 ; b=2015;c=2016
Rut gon bieu thuc: (a-b+c)^2+2(a-b+c)(b-c)+(b-c)^2
Dùng hằng đẳng thức A2 + 2AB + B2 = ( A + B)2 :
Ta được ... = (a-b+c+b-c)2 = a2