The answer is A
there is not enough hours to build everything and A has the right equation
Answer:

Step-by-step explanation:

Add 4 to both sides

Divide both sides by 3

Hope this helps!
(Please mark brainliest)
Answer:
(7, 6)
Step-by-step explanation:
multiply first eq. by 3 to get 6x - 3y = 60
now do
6x + 3y = 60
- 6x - 5y = 12
--------------------
8y = 48
solve for y: y = 6
with this y value, plug it in to the first equation (easier to solve) and get 2x + 6 = 20
solve for x and get x = 7
so ans is (7, 6)
Answer:
(5a - [2b - 7c]) and (5a + [2b + 7c])
Step-by-step explanation:
Factor 25a^2 - 4b^2 + 28bc - 49c^2.
Note that - 4b^2 + 28bc - 49c^2 involves the variables b and c, whereas 25a^2 has only one variable. Thus, try to rewrite - 4b^2 + 28bc - 49c^2 as the square of a binomial:
- 4b^2 + 28bc - 49c^2 = -(4b^2 - 28bc + 49c^2), or
-(2b - 7c)^2.
Thus, the original 25a^2 - 4b^2 + 28bc - 49c^2 looks like:
[5a]^2 - [2b - 7c]^2
Recall that a^2 - b^2 is a special product, the product of (a + b) and (a - b). Applying this pattern to the problem at hand, we conclude:
Thus, [5a]^2 - [2b - 7c]^2 has the factors (5a - [2b - 7c]) and (5a + [2b + 7c])