Let us denote the number of tiles by

.
In the first store, if Darin bought

tiles, he would need to spend:

(measured in $)
In the second store, if Darin bought

tiles, he would need to spend:

(measured in $)
For the cost to be the same at both stores, it means (measured in $)

Moving

over to the left hand side and changing signs:

tiles
Let's check. If he buys 60 tiles in the first store, he spends:
$0.79×60 + $24 = $47.40 + $24 = $71.40
If he buys 60 tiles in the second store, he spends:
$1.19×60 = $71.40
∴
Darin needs to buy 60 tiles for the cost to be the same at both stores.
Answer:
By making ‘a’ the subject, I believe you mean isolate the variable ‘a’.
1/a - 1/b = 1/c : add 1/b to both sides
1/a = 1/b + 1/c : combine the unlike fractions by finding a common denominator, bc is the common denominator
1/a = (1/b)(c/c) + (1/c)(b/b) : simplify
1/a = (c/bc) + (b/bc) : add numerators only, because the denominators match
1/a = (c + b)/bc : multiply both sides by a
1 = (a)[(c + b)/bc] : multiply both sides by the reciprocal of [(c + b)/bc] which is [bc/(b + c)]
1[bc/(b + c)] = a
a = bc/(b + c)
This will not work if c = -b, because then you would be dividing by zero.
Example: 1/2 - 1/3 = 1/6 a = 2, b = 3 c= 6
a = bc/(b + c) => 2 = (3 x 6)/(3 + 6) => 2 = 18/9 => 2 = 2.
Step-by-step explanation:
I don’t know but it is really annoying and they need to stop. they are virus’
Answer:
90
Step-by-step explanation:
The LCM of 2 and 45 is 90.