1) (3-√13) ⋅ (3+√13) =

2) 3√5-√80+31√20=

3) 3 (x-8) - 1,2x+1,2=

4) x²-2x-8=0

Question

Математика

Станимир

20 декабря, 03:49

1) (3-√13) ⋅ (3+√13) =

2) 3√5-√80+31√20=

3) 3 (x-8) - 1,2x+1,2=

4) x²-2x-8=0

+2

Ответы (1)

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Галинуха · Answer 1

1) (3-√13) · (3+√13) = 3²-13=-4

2) 3√5-√80+31√20=√5· (3-4+62) = 61√5

3) 3 (x-8) - 1,2x+1,2=3x-24-1,2x+1,2=1,8x-22,8

4) x²-2x-8=0

D=4-4 * (-8) = 6²

x₁ = (2+6) / 2=4

x₂ = (2-6) / 2=-2

1) (3-√13) ⋅ (3+√13) =2) 3√5-√80+31√20=3) 3 (x-8) - 1,2x+1,2=4) x²-2x-8=0

1) (3-√13) ⋅ (3+√13) =

2) 3√5-√80+31√20=

3) 3 (x-8) - 1,2x+1,2=

4) x²-2x-8=0