Question

用因式分解法解一元二次方程:3(x–5)²=25–x²

Answer 1

3(x-5)^2=25-x^2

3(x-5)^2+(x^2-25)=0

3(x-5)^2+(x-5)(x+5)=0

(x-5)[3(x-5)+(x+5)]=0

(x-5)(4x-10)=0

x=5或x=5/2