Answer:
b=-3
Step-by-step explanation:
-7b=21
-7b/-7=21/-7
b=-3
I haven't done this kind of work in a bit, but I believe it's 8.

Step-by-step explanation:


<em>Prologarithmize both parts of the equation:</em>

<u><em> Divide both parts of the equation by 2:</em></u>


We can see that
both lines intersects at origin
so, the solution is x=0 and y=0
now, we will check each options
option-A:


now, we can set them equal
and then we can solve for x



now, we can find y


so, solution is x=0 and y=0
so, this correct...........Answer