Question

Cho a+b=3 ab=-5 Tính A=a^2+b^2 B=a^4+b^4

Answer 1

\(A=a^2+b^2=\left(a+b\right)^2-2ab=3^2-2.\left(-5\right)=19\)

\(B=a^4+b^4=\left(a^2+b^2\right)^2-2\left(ab\right)^2=19^2-2.\left(-5\right)^2=311\)