Question

rozwiaz rownanie:

4(x+1)do kwadratu - 25=0

Proszę o szbką pomoc

Answer 1

4 ( x +1)^2 -25 = 0

4 *(x^2 +2x + 1) - 25 = 0

4 x^2 +8x + 4 - 25  = 0

(2x + 2)^2  - 25 = 0

(2x + 2 - 5)*(2x + 2 +5) = 0

(2x -3)*(2x + 7) = 0

2x - 3 = 0  lub 2x + 7 = 0

2x = 3   lub  2x = - 7

x = 1,5   lub x = - 3,5

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II sposób:

4 x^2 + 8x - 21 = 0

delta = 64 -4*4*(-21) = 64 + 336 = 400

x1 = [ -8 - 20]/8 = -28/8 = -3,5

x2 = [ -8 + 20]/8 = 12/8 = 1,5

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