Answer:
X/2-7
Step-by-step explanation:
any number which is said to be less than another number let's say b should be subtracted from b.
If you mean "how to write the sum", the answer is

The result of this sum is
, because you start from 2 on the number line and take 3 steps to the left (negative integers mean going left, positive integers mean going right)
The correct answer is quadrant.
Quadrant is a method used to determine latitude. Chronometer is used to measure time. Astrolabe is used by navigators and astrologers. Cross-staff or Jacob's staff is used to measure angles. So the correct answer would be quadrant. I hope this helped you.
Consider the number 480 in expanded form:
... 480 = 4×100 + 8×10
The left-most digit and multiplier are those that correspond to the ones you use in scientific notation.. You recall that 100 = 10×10 = 10². All this means is that
... 480 = 4.8×10²
A ) equation would be X = Z / Y
B ) if X = 9 ------------> Y = 1/7
X = 21 ----------> Y = ?
21*1/7 = 21/7 , 21/7÷9 = 21*9/7 = 27
so Y equal 27