fonction affine =ax+b
g(4) = 1 ........... 4a+b = 1
g(5) = -4 .......... 5a+b = -4
4a+b = 1
5a+b = -4
systeme à résoudre :
b = -4a+1
5a+(-4a+1) = -4
a = -4-1
a = -5
5a+b = -4
-25+b =-4
b = 21
g(x) = -5x+21
exo 5 :
singHi = IH/GH = 2,7/4,9 = 0,55
sin0,55 = 33,36° arrondi 33°
exo 1 :
a) 20x²-50x-70
b) x-7)(12x+3-2x+7) =
(x-7)(10x+10) =
10(x-7)(x+1)
c) 20x²-50x-70 =
20(2)² - (50*2) -70 =
80-100-70 = -90
20(-1)² - (50*-1) - 70 =
20+50-70 = 0
d) 10(x-7)(x+1) = 0
x-7 = 0
x =7
x+1 = 0
x = -1