Question

{y²-[6²-(8²-9*7)³-7*5³]-5*3}³=1

 

Answer 1

=>{y^2-36+(64-63)^3+7*125-15}^3=1

=>{y^2-51+875+1}=1

=>y^2=-824(vô lý)

Answer 2

\(\left\{y^2-\left[6^2-\left(8^2-9\cdot7\right)^3-7\cdot5^3\right]-5\cdot3\right\}^3=1\)

\(\Rightarrow\left\{y^2-\left[6^2-\left(64-63\right)^3-875\right]-15\right\}^3=1\)

\(\Rightarrow\left\{y^2-\left[36-1^3-875\right]-15\right\}^3=1\)

\(\Rightarrow\left[y^2-\left(-840\right)-15\right]^3=1\)

\(\Rightarrow\left(y^2+840-15\right)^3=1\)

\(\Rightarrow\left(y^2+825\right)^3=1\)

\(\Rightarrow\left(y^2+825\right)^3=1^3\)

\(\Rightarrow y^2+825=1\)

\(\Rightarrow y^2=1-825\)

\(\Rightarrow y^2=824\)

\(\Rightarrow y=2\sqrt{206}\)