Question

Exercitiile 2 si 5 va rog!

Answer 1

2

a) $[(-9)^{n}]^{2}=81^3$ . In acest caz pentru usurinta schimbam locul puteriilor 2 si n:

$[(-9)^{2}]^{n}=81^3 <=> 81^n=81^3 => n=3$

b) $(+8)^n*(-3)^n=(-24)^6$. 24 poate fi scris ca si 8*3 si atunci avem:

$(+8)^n*(-3)^n=(-3*8)^6$<=>$(+8)^n*(-3)^n=8^6*(-3)^6 => n=6$

c) $(-8)^n*(+18)^n=(-144)^5$ <=> $(-8)^n*(+18)^n=(-8*18)^5 <=> (-8)^n*(+18)^n=(-8)^5*(18)^5$ => n=5

d) $[(-12)^2]^n=144^3 <=> 144^n=144^3 => n=3$

5

a) 3x+5-2(x+2)=8-3(1-x) <=> 3x+5-2x-4=8-3+3x <=> x-1=5+3x <=> -2x=4 <=> x=-2

b) 3(2x+1)-4(x+3)=5-2(2x+1) <=> 6x+3-4x-12=5-4x-2 <=> 2x-9=3-4x <=> 6x=12 <=> x=2