thu gon bieu thuc sau:
135.234+135.324-135.556
Thu gon bieu thuc sau roi tim gia tri cua x de bieu thuc co gia tri la so am
7 × -19 × x + 6 × x
x+2x+4x+...+125x+126x bang cach thu gon cac bieu thuc sau:
Đề không đúng
Tự dưng 1x+2x+4x+......+125x + 126x là sao
thu gon bieu thuc sau:
x+2x+3x+4x+...+125x+126
thu gon bieu thuc sau (2x-1)^3-(3x^2-1)(x-2)-(x+3)^3
Ta có: \(\left(2x-1\right)^3-\left(3x^2-1\right)\left(x-2\right)+\left(x+3\right)^3\)
\(=8x^3-12x^2+6x-1-\left(3x^3-6x^2-x+2\right)+x^3+9x^2+27x+27\)
\(=9x^3-3x^2+33x+26-3x^3+6x^2+x-2\)
\(=6x^3+3x^2+34x+24\)
Thu gon cac bieu thuc sau
7x - 19x + 6x
-ab - ab
thu gon bieu thuc
(x+1)^3-x(x^2+3)
thu gon bieu thuc sau:
\(\sqrt{4+\sqrt{15}}+\sqrt{4-\sqrt{15}}-\sqrt{3-\sqrt{5}}\)
thu gon roi tinh bieu tri cua bieu thuc;
d=(10-a+b)-(10-b+c)-(10-c-a)
D=(10-a+b)-(10-b+c)-(10-c-a)
D= 10-a+b-10+b-c-10+c+a
D=(10-10-10)-(a-a)+(b+b)-(c-c)
D= -10+2b
Ai giup m voi: Thu gon roi tinh bieu thuc sau:
C= x^5 - 5x^4 + 5x^3 - 5x^2 + 5x -1 voi x=4
Dễ thấy 5=4+1=x+1
Thay vào C,ta có:
\(C=x^5-\left(x+1\right)x^4+\left(x+1\right)x^3-\left(x+1\right)x^2+\left(x+1\right)x-1\)
\(=x^5-x^5-x^4+x^4+x^3-x^3-x^2+x^2+x-1=x-1=4-1=3\)