7.
Объяснение:
log2(4x-20)=3, x>5
log2(4(x-5))=3
log2(4)+log2(x-5)=3
log2(2^2)+log2(x-5)=3
2+log2(x-5)=3
log2(x-5)=1
x-5=2^1
x-5=2
x=7
7.
Объяснение:
log2(4x-20)=3, x>5
log2(4(x-5))=3
log2(4)+log2(x-5)=3
log2(2^2)+log2(x-5)=3
2+log2(x-5)=3
log2(x-5)=1
x-5=2^1
x-5=2
x=7