Question

E(x)=(2x+1)²-2(x+3)(x-1) determinați x stiind ca E(x)=9​

Answer 1

Explicație pas cu pas:

E(x)=4x²+4x+1-2(x²+2x-3)=>

E(x)=4x²+4x+1-2x²-4x+6=>E(x)=2x²+7

E(x)=9=>2x²+7=9=>2x²-2=0=>2(x²-1)=0=>

x²-1=0=>(x+1)(x-1)=0=>x1=1 sau x2=-1