Question

1). 6(2x+3)+4(x-3) <3(3x-2)+37
2). Daca a-1/a=3 ,a nu este 0;apartine numerelor R,atunci a(la patrat)+1/a(la patr.)egal?
Va rog sa fiti mai exacti,ca sa inteleg

Answer 1

1) 12x + 18 +4x -12 < 9x -6 +37

16x +6 < 9x +31

16x -9x < 31 -6

5x < 25  |:5

x < 5   => x=(-α;5)

2)$\frac{a-3}{a}=3 <=> a-3=3a <=> a-3a = 3 <=> -2a =3 => a= -\frac{3}{2} \\ \frac{a-1}{a}=3 \ \ |^2 <=> \frac{(a-1)^2}{a^2}=9 <=> \frac{(a-1)(a+1)}{a^2}=9 \\ \frac{( - \frac{3}{2} -1)(a+1)}{a^2}=9 \ aducem \ la \ acelasi \ numitor\ la \ numarator \ \\ \frac{ (\frac{-3-2}{2})(a+1)}{a^2}=9 <=> \frac{ -\frac{5}{2}(a+1) }{a^2} =9 \\ \frac{a+1}{a^2}= 9 * ( -\frac{2}{5}) <=> \frac{ a+1}{a^2}= -\frac{18}{5}$