How do you solve and graph x^2-1>=4x?
1 Answer
Aug 28, 2017
Explanation:
color(blue)"graphing the parabola"
x^2-4x-1>=0larr" rearranging"
"with "a=1,b=-4,c=-1
"find zeros using the "color(blue)"quadratic formula"
x=(4+-sqrt(16+4))/2=2+-sqrt5
rArrx~~ -0.24" or "x~~ 4.24
"since "a>0" then minimum turning point "uuu
"to find the vertex "color(blue)"complete the square"
x^2-4x+4-4-1
rArr(x-2)^2-5
rArrcolor(magenta)"vertex "=(2,-5)
"the solution to the inequality are the values of x "
"above the x-axis"
graph{x^2-4x-1 [-10, 10, -5, 5]}
rArr(-oo,2-sqrt5)uu(2+sqrt5,+oo)
