Răspuns:
Explicație pas cu pas:
Partea I:
1.
-2*2√3 : -√3 = 4
2.
(x + 7)^2 = x^2 + 14x + 49
3.
x/6 = 1/3 - 3/3 = -2/3 = -4/6
x = -4
4.
I^2 = 9 + 16 = 25
I = 5 cm
5.
L = 4 cm
H = inaltimea
H^2 = L^2 - (L/2)^2 = 16 - 4 = 12
H = √12 = 2√3 cm
A = L*H/2 = 4 *2√3/2 = 4√3 cm^2
6.
sin C = 1/2 rezulta C = 30 grade, rezulta B = 60 grade; cos 60 = 1/2
Partea a II-a
1.
Prima zi 25% = 25/100 = 1/4
A doua zi 1/6
Rest 1 - (1/4 + 1/6) = 12/12 - (3/12 + 2/12) = 12/12 - 5/12 = 7/12
7D/12 = 28 km
D = 12*28/7 = 48 km (lungimea drumului)
2.
a)
4x^2 - (2x - 3)^2 = 0
4x^2 - (4x^2 - 12x + 9) = 0
4x^2 - 4x^2 + 12x - 9 = 0
12x = 9
x = 9/12 = 3/4
_________
b)
4 - 2(3x - 2) ≥ x - 25
4 - 6x + 4 ≥ x - 25
7x ≤ 8 + 25
7x ≤ 33
x ≤ 33/7
x = {1, 2, 3, 4]
___________________
a = 2/√2 - (2 - √2) = √2 - 2 + √2 = 2√2 - 2
b = 2 + √8 = 2 + 2√2
a x b = (2√2 - 2)(2√2 + 2) = 8 - 4 = 4
Mg = √axb = √4 = 2
