4.5/2.5 = y/12
y = 12 * 4.5/2.5
y = 21.6
-8 ........................
Answer:
Option A is correct
the expression is equal to
is 
Explanation:
Given expression is, 
Multiply and divide by the denominator by
in the given expression, we have,

or

use : 
then;

Therefore, the expression is equal to
is, 
Answer:
6+f=21
Step-by-step explanation:
Answer:
x + 14 = 2(x + 6)
x = 2
Step-by-step explanation:
Let
Algebra book age = x
Chemistry book age = x + 8
In 6 years time
Chemistry book age = x + 8 + 6
= x + 14
Algebra book age = x + 6
the chemistry book will be twice as old as the Algebra book.
x + 14 = 2(x+6)
x + 14 = 2x + 12
x - 2x = 12 - 14
- x = - 2
Divide both sides by -1
x = 2
Check:
Chemistry book age = x + 14
= 2 + 14
= 16
Algebra book age = x + 6
= 2 + 6
= 8