Answer:the pages will come on the first is 210
Explanation:
Since we have given that two pages that face each other in a book
i.e. they must be consecutive to each other
so, let the first page number be x
and the second page number be x+1
According to question,

2x=421 -1
2x=420

So, the pages will come on the first is 210
All you have to do is move the denominator on the other side, by multiplying.
a-10
------- = -9
20
multiply 20 x -9
= -180
then it becomes a-10=-180
+10 +10
a=-170
The <span>Pythagorean theorem</span> is what is most useful here, and a calculator; for the following...
Imagine forming a triangle by creating that last leg between the starting position and the ending position; the length of that side will be our missing variable "y".
600<span>² + 800</span>²= y<span>²
The sum of the two (600</span><span>² & 800</span>²) must then be square rooted to find the length
y² = 1,000,000 and the square root of y<span>²= 1,000 (YOUR ANSWER) "y"</span>
(2,-4) is new reflected coordinates