Question

What are the solutions of –x2 + 4x = x – 4?

Answer 1

Hello,
-x²+4x=x-4;
-x²+4x-x+4=0
-x²+3x+4=0
x²-3x-4=0
∆=b²-4ac=(3)²-4(-4)(1)=9+16=25
x₁,₂=-b±√∆/2a=3±5/2
x₁=3-5/2=-2/2=-1
x₂=3+5/2=8/2=4

Therefore the solutions are
x=-1 and x=4

bye :-)