Problemx2+4x+4=0x^2 + 4x + 4 = 0x2+4x+4=0Step-by-step solution辨認為 (a+b)2=a2+2ab+b2(a + b)^2 = a^2 + 2ab + b^2(a+b)2=a2+2ab+b2，其中 a=xa = xa=x、b=2b = 2b=2。分解：(x+2)2=0(x + 2)^2 = 0(x+2)2=0。求解：x=−2x = -2x=−2 — 重根。Answerx=−2(double root)x = -2 \quad \text{(double root)}x=−2(double root)Want to solve a different problem? Open the quadratic solver →Related worked examples/solve/algebra/x2-plus-2x-plus-1