Question

15 - x² = x - 1 помогите по братски​

Answer 1

$15-x^2=x-1\\15-x^2-x+1=0\\-x^2-x+16=0\\x^2+x-16=0\\D=1-4\cdot1\cdot(-16)=1+64=65\\x_{1,2}=\frac{-1\pm\sqrt{65}}2\\\\x_1=\frac{-1-\sqrt{65}}2,\;\;\;\;x_2=\frac{-1+\sqrt{65}}2$