Question

Minim 3 exercitii la alegere ! ​

Answer 1

Răspuns:

Explicație pas cu pas:

1.

√75 = 5√3

√20 = 2√5

√125 = 5√5

(-1/2)^-1 = -2

5√3*2√5*(-2) - 5√3*5√5*(-2) = -20√15 + 50√15 = 30√15

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2.

2(-6 + 3a) + 5 = 11

2(-6 + 3a) = 11 - 5 = 6

-6 + 3a = 6 : 2 = 3

3a = 3 + 6 = 9

a = 9 : 3 = 3

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3.

(-x + 3)^2 +4(x + 1) = x^2 - 6x + 9 + 4x + 4 = x^2 - 2x + 13

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4.

(x + y)^2 = x^2 + 2xy + y^2

2xy = (x + y)^2 - (x^2 + y^2) = 98 - 50 = 48

xy = 48 : 2 = 24

Mg = √xy = √24 = 2√6

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5.

L x l = 48

L = 3 x l

3 x l  x l = 48

l x l = 48 : 3 = 16

l = √16 =4 cm

L = 4 x 3 = 12 cm

P = 2x l + 2 x L = 8 + 24 = 32 cm

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6.

x(x + 1) ≤ (x - 3)^2

x^2 + x ≤ x^2 - 6x + 9

x^2 + x - x^2 + 6x  ≤ 9

7x ≤ 9

x ≤ 9/7

x = {0, 1}