3x-21=57
3x=21+57
3x=78
Divide by 3
X=26
.
Step-by-step explanation:
<span>−8x+7y=25 is already in standard form, altho some people would prefer to re-write it as
</span><span>−8x+7y-25 = 0.
You have shared 4 equations here. Next time, please separate them with commas or semi colons, or type just 1 equation per line, for increased clarity. Thanks.</span>
Answer:
The expression is true.
Explanation:

We know that (a +b)(a-b) = a²-b²
So we have ,

Which is Right Hand Side given.
So, the expression is true.
The nth term is 2n +1 and the 43rd term is 87