1.|x| = x pt. x > 0 si -x pt. x<0
Pt. x > 0 => 2x - x +3 = 0 > x = -3 nu este pozitiva
Pt. x < 0 => 2x-(-x) +3 = 0 > 3x = -3, x = -1 => A={-1}
2.f(x) >=0 daca are forma (x+a)^2 + b , cu b > 0
f = (x-(m-1))^2 -(m-1)^2 + m +5 => -(m-1)^2 + m +5 > 0
-m^2 +2m -1 +m+5 =-m^2+3m+4 >= 0, delta = 9+16=25 => m=-1 si m=4
-m^2+3m+4 >= 0 ptr. m intre radacini => -1 <= m <= 4
3. Comb.de 10 luate 2 = comb. 10 Luate 8 (compl.) => rez. = 0
4. Term 4: (comb.de 7 cu3)*((radx)^4)*((1/(radx))^3) = (7*6*5/2*3)(x^2)*(1/(x^2)*(1/radx)) = 35*(1/radx)5.a*b = 3*1i + (-2*4)j = 3i - 8j
6. Dist. dintre un punct M(x1,y1) si o dreapta ax + by + c = 0 este: | a*x1 + b*y1 +c |/(rad(a^2 + b^2)) dr.BC = (x-(-2))/(2-(-2)) = (y-1)/(-3-1) => (x+2)/4=(y-1)/(-4) -4x - 8 = 4y -4 => -4x -4y -4=0 |(-4) => x + y + 1 = 0 dist(A,dr.)= |1*1 + 2*1 + 1|/(rad(1+1)) = 5/rad2
