4^2*(b^14)^2*(x^11)^2=(4*b^14*x^11)^2.
7^[x]=8....................................................................................
x=log7(8)
ОДЗ
{x-3≥0⇒x≥3
{x-9≥0⇒x≥9
x∈[9;∞)
(√(x-3)²=(x-9)²
x-3=x²-18x+81
x²-19x+84=0x1+x2=19 U x1*x2=84
x1=7 не удов усл
x2=12