1. g(-4) = 1-2*(-4)² = 1-2*16 = 1-32 = -31
g(3/4) = 1-2*(3/4)² = 1-2*(9/16) = 1-9/8 = -1/8
g(√2) = 1-2*(√2)² = 1-2*2 = 1-4 = -3
g(5) = 1-2*(5)² = 1-2*25 = 1-50 = -49
2. 1-2x² = 0
-2x²=-1
x²=1/2
donc x = -√1/2 ou √1/2
1-2x²=-26
-2x²=-26-1
-2x²=-27
x²=27/2=13,5
donc x = -√13,5 ou √13,5
