Taco

\(\dfrac{\text{∠}A}{4}=\dfrac{\text{∠}B}{3}=\dfrac{\text{∠}C}{2}=\text{∠}D\)

Áp dugj dãy tỉ số = nhau ta cs \(\dfrac{\text{∠}A}{4}=\dfrac{\text{∠}B}{3}=\dfrac{\text{∠}C}{2}=\text{∠}D=\dfrac{\text{∠}A+\text{∠}B+\text{∠}C+\text{∠}D}{4+3+2+1}\)

=\(\dfrac{360}{10}=36\)

\(=>∠A=144^o ∠B=108^o ∠C=72^o ∠D=36^o\)

\(\)\((2a-b+3c)^2\)

\(=4a^2+b^2+9c^2-2.4ab-2.3bc+2.6ac\)

\(=4a^2+b^2+9c^2-8ab-6bc+12ac\)

\(G=3(x^2+2x-3)-(3x^2+5x-10)\)

\(ma x^3=27=>x=3\)

\(G=3(3^2+2.3-3)-(3.3^2+5.3-10)=4\)

a)Taco AB^2=\(\sqrt{BC^2-AC^2}=\sqrt{15^2-12^2}=9\)

A)=-325

B)=100

c)=1000

Thiếu đề nè

D)

Mình làm trên Word nên hoi khó nhìn