Toán Lớp 8: Tìm X bt;
e/ (x+2)^2-(x-2)(x+2)=0
giúp!!!!!!!!!!!!!
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Toán Lớp 8: Tìm X bt;
e/ (x+2)^2-(x-2)(x+2)=0
giúp!!!!!!!!!!!!!
Comments ( 2 )
Answer
(x + 2)^2 – (x – 2) . (x + 2) = 0
=> x^2 + 4x + 4 – x^2 + 4 = 0
=> (x^2 – x^2) + 4x + (4 + 4) = 0
=> 4x + 8 = 0
=> 4x = 0 – 8
=> 4x = -8
=> x = -8 : 4
=> x = -2
Vậy x = -2
Giải đáp:
x = -2
Lời giải và giải thích chi tiết:
(x + 2)² – (x – 2)(x + 2) = 0
⇔ (x + 2)² – (x² – 2²) = 0
⇔ x² + 2.2.x + 2² – x² + 2² = 0
⇔ (x² – x²) + (2² + 2²) + 4x = 0
⇔ 8 + 4x = 0
⇔ 4x = 0 – 8
⇔ 4x = -8
⇔ x = -8 : 4
⇒ x = -2