Question

Can someone please help me on this math problem. I don't understand it

Answer 1

`f(x)=x^2-2x-8\\\\g(x)=x-1\\\\f(x)=g(x)\to x^2-2x-8=x-1\ \ \ |-x+1\\\\x^2-3x-7=0`

Use the quadratic formula:


`ax^2+bx+c=0\\\\x_1=(-b-√(b^2-4ac))/(2a);\x_2=(-b+√(b^2-4ac))/(2a)`


`x^2-3x-7=0\\\\a=1;\ b=-3;\ c=-7`

substitute


`b^2-4ac=(-3)^2-4\cdot1\cdot(-7)=9+28=37\\\\√(b^2-4ac)=√(37)\approx6.083`


`x_1=(-(-3)-√(37))/(2\cdot1)=(3-√(37))/(2)\approx(3-6.083)/(2)=-1.54\\\\x_2=(-(-3)+√(37))/(2\cdot1)=(3+√(37))/(2)\approx4.54`

there is no that answer to choose from

I also have such answers in the graphical method (look at the picture).