bonjour
2 a + 2 b = 38 donc a + b = 19
a + b = 19
ab = 60
a = 19 - b
ab = ( 19 - b) b = - b² + 19 b
- b² + 19 b = 60
- b² + 19 b - 60 = 0
Δ = 19 ² - 4 ( - 1 * - 60) = 361 - 240 = 121 = 11 ²
x 1 = ( - 19 - 11 ) / - 2 = - 30 / - 2 = 15
x 2 = ( - 19 + 11 ) / - 2 = - 8 / -2 = 4
dimensions = 4 m sur 15 m
P = 2 x 19 = 38
A = 4 * 15 = 60
