Question

решите уравнение (x-2)^2-9=0
СРОЧНО!!!

Answer 1

x²-4x+4-9=0
x²-4x-5=0
D=(-4)²-4*1*(-5)=16+20=36
x₁=(4+6)/2=10/2=5
x₂=(4-6)/2=-2/2=-1

Answer 2

$(x-2)^2-9=0\\(x-2)^2-3^2=0qquad quad [; a^2-b^2=(a-b)(a+b); ]\\(x-2-3)(x-2+3)=0\\(x-5)(x+1)=0\\x-5=0; ; ; to ; ; ; x=5\\x+1=0; ; ; to ; ; ; x=-1$