Answer:
Step-by-step explanation:
Let's say the Physics book costs $x
The Chemistry book will cost $x - $6
Two such Chemistry books will cost;
2($x - $6) = $(2x - 12)
Three such Physics books cost $3x
$(2x - 12) + $3x = $123
$5x - $12 = $123
$5x = $111
x = $22
So the Physics book costs; $22
and the Chemistry book costs $22
- 6 = $16
Answer:
-12x+12y
Step-by-step explanation:

Hope this helps!
Answer:
AE = 18 units
Step-by-step explanation:
Δ AEB and Δ DEC are similar , then corresponding sides are in proportion, that is
=
, substitute values
=
( cross- multiply )
10(2x + 4) = 12(x + 8) ← distribute parenthesis on both sides
20x + 40 = 12x + 96 ( subtract 12x from both sides )
8x + 40 = 96 ( subtract 40 from both sides )
8x = 56 ( divide both sides by 8 )
x = 7
Then
AE = 2x + 4 = 2(7) + 4 = 14 + 4 = 18 units
Answer:

Step-by-step explanation:
The given function is
f(x) = 4x
As we know
f(x) = y, which implies x= 
Therefore,
y = 4x
x = 
as x= 
So,

replacing y by x in the above expression

So our inverse function is 
2-1/4
2/1=8/4 Multiply top and bottom by 4
8/4-1/4
7/4
1 3/4