Since these are all like terms, you're essentially just adding and subtracting here.
Add 
and 
.
Then, subtract.
Your answer is 
.
I don't know if it's 74, but I got -80. here's how:
(3x + 5 x -4x + 7) (-4)
(8 x -4x + 7) (-4)
(8 x 3) (-4)
24 x -4 = -80
We can use the subtraction property of logs to expand the right side of the equation:
log(1/H*) = log(1) - log(H*)
No matter what base we’re using, log(1) = 0, so this simplifies to -log(H*). We’re also given a pH value of 3.6, so we can substitute this value into the original equation along with -log(H*) to get
3.6 = -log(H*)
Multiplying by -1 on both sides:
-3.6 = log(H*)
And rewriting in exponential form:
H* = 10^(-3.6) = 0.0003 (rounded to the nearest ten thousandth)
The perimeter is everything added up, since its not a square then you add not multiply. 24+24=48 and 16+16=32, add 32 and 48 and get 80. Answer:80
