Question

已知丨x-2丨+丨y-1/2丨+丨z-3丨=0,求5（x-2y）-z的值

Answer 1

∣x-2∣+∣y-1/2∣+∣z-3∣=0 ∴∣x-2∣=0 ∣y-1/2∣=0 ∣z-3∣=0 x=2 y=1/2 z=3 5(x-2y)-z=5(2-2*1/2)-3=5-3=2