Răspuns:
Explicație pas cu pas:
1b) -3 -log2(2^-3) = -3 +3= 0
c) lg250*4 = lg1000 = lg10^3 = 3
d) log6(8*9) -log6(2) = log6(72/2) = log6(6^2) = 2
2a) 2x +3 = 25, 2x = 22, x = 11
b) 2x -1 = 3^3=27, 2x -2 = 26, x = 13
c) 5^(3x -7) = 5^2
3x -7 = 2, 3x = 9, x = 3
d) log2(x^2 +7) = log3(2^3)
x^2 +7 = 8, x^2 = 1, x = -+1, x1 = -1, x2 = 1
e) 5^(x^2 -5x +7) = 125 = 5^3
x^2 -5x +7 = 3
x^2 -5x +4 = 0
(x-1)(x -4) = 0, x1 = 1, x2 = 4
etc.
