1.
[tex]log_a b \\
a>0 \hbox{ and } a \not=1 \\
b>0 \\ \\
log_4 (x+3) \\
x+3>0 \\
x>-3[/tex]
log₄(x+3) is defined for x greater than -3.
0>-3
-2>-3
3>-3
4≤-3
The answer is D. -4.
2.
[tex]\log 7=a \\ \\
\log 490= \log (7^2 \cdot 10)=\log 7^2 + \log10=2 \log 7 + 1=2a+1[/tex]
The formulas I used:
[tex]\log_a (x \cdot y)=\log_a x + \log_a y \\
\log_a x^y=y \log_a x \\
\log x=\log_{10} x[/tex]
3.
[tex]y=\log_7 x \\ \\
(1,k) \\
x=1 \\ y=k \\ \\
k=\log_7 1 \\
k=\log_7 7^0 \\
k=0[/tex]