a,bc + ab,c = 21,12

<=> a,bc + a,bc x 10 = 21,12

<=> 11 x a,bc = 21,12

<=> a,bc = 1,92

=> a = 1, b = 9; c = 2

Nếu thấy bài làm mình đúng thì nhớ tick ủng hộ nhé!!!

tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttyttttttttttttttttttttttttttttttttttttttttttttytyytytytyttytytytytytytytytytytytytytytytyt

gọi rùi phân tick cấu tạo số

a) \(P_{\left(x\right)}+Q_{\left(x\right)}=x^3-2x+1+2x^2-2x^3+x-5\)

\(=\left(x^3-2x^3\right)+\left(-2x+x\right)+2x^2+\left(1-5\right)=-x^3-x+2x^2-4\)

b) \(P_{\left(x\right)}-Q_{\left(x\right)}=x^3-2x+1-2x^2+2x^3-x+5\)

\(=\left(x^3-2x^3\right)+\left(-2x-x\right)-2x^2+\left(1+5\right)=-3x^3-3x-2x^2+6\)

\(3^{x+1}.4^y=36^x\)

\(\Rightarrow3^{x+1}+4^y=\left(4.3^2\right)^x\)

\(\Rightarrow3^{x+1}+4^y=4^x+3^{2x}\)

\(\Rightarrow4^y-4^x=3^{2x}-3^{x+1}\)

\(\Rightarrow4^y-4^x=\left(3^x\right)^2-3^x+3\)

Bài 1 : \(\sqrt{12}+\sqrt{27}-\sqrt{3}\)

\(=\sqrt{4.3}+\sqrt{9.3}-\sqrt{3}\)

\(=2\sqrt{3}+3\sqrt{3}-\sqrt{3}\)

\(=\sqrt{3}\left(2+3-1\right)\)

\(=4\sqrt{3}\)

Bài 2 : Ta có : \(A=\left|x-1004\right|-\left|x+1003\right|\)

\(\Rightarrow A\le\left|1004-x+x+1003\right|\)

\(\Rightarrow A\le2007\)

Vậy dấu "=" xảy ra khi MaxA = 2007