Question

ALGUÉM RESPONDE ESSA LETRA "B" PRA MIM POR FAVOR??????PLEASEEEEE

Answer 1

${x}^{2} - {y}^{2} = 81 \\ \frac{x}{y} = \frac{5}{4}$
x^2=81+y^2
x=√81+√y^2
x=9+y

substituir

9+y/y=5/4
9+y=5y/4
(5y/4)-y=9
y/4=9
y=9*4
y=36

x^2-36=81
x^2=81+36
x^2=117

x=117
y=36