Question

qual o valor de x na equação a seguir? $(x+1)^{2}$ -8(x-1)=0

Answer 1

• (x + 1)^2 - 8(x - 1) = 0
• x^2 + 2 . x . 1 + 1^2 - 8(x - 1) = 0
• x^2 + 2x . 1 + 1 - 8(x - 1) = 0
• x^2 + 2x + 1 - 8(x - 1) = 0
• x^2 + 2x + 1 - 8 . x - 8 . (-1) = 0
• x^2 + 2x + 1 - 8x - (-8) = 0
• x^2 + 2x + 1 - 8x + 8 = 0
• x^2 + 2x - 8x + 1 + 8 = 0
• x^2 + (-6x) + 1 + 8 = 0
• x^2 - 6x + 1 + 8 = 0
• x^2 - 6x + 9 = 0
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a = 1 // b = -6 // c = 9



- b +/- √∆
• ━━━━
2a

- b +/- √(b^2 - 4ac)
• ━━━━━━━━━
2a

- (-6) +/- √((-6)^2 - 4 . 1 . 9)
• ━━━━━━━━━━━━
2 . 1

6 +/- √(36 - 4 . 9)
• ━━━━━━━━
2

6 +/- √(36 - 36)
• ━━━━━━━
2

6 +/- √0
• ━━━━
2

6 +/-
• ━━━
2

6
• ━
2


━━━┓
x = 3