aria = cat₁· cat₂ / 2
24 = ( x + 4) · ( 5x -2 ) /2
( x +4) · ( 5x -2) = 48
5x² + 18x - 56 = 0
Δ = 324 + 1120 =1444 ; √Δ =38
x = ( - 18 - 38 ) / 10 = - 56 /10 negativ , fals
x = ( - 18 + 38 ) / 10 = 2
catetele 6 si 8
ipotenuza i² = 6² + 8² = 100
i = √100 =10
