Look at the picture.
We have the equation (1) 12x + 4y = 40.
We know, the sum of the acute angles in a right triangle is 90°.
Therefore we have the equation (2) (12x + 4y) + (17x - y) = 90
Substitute (1) to (2):
40 + 17x - y = 90 <em>subtract 40 from both sides</em>
17x - y = 50 (3)
We have the system of equations:

Substitute the value of x to (3)

Answer: x = 3 and y = 1.
Answer:
ummm i think its B?
Step-by-step explanation:
Answer:
$65.60
Step-by-step explanation:
4×16.40 = 4×(16+0.40) = (4×16) + (4×0.40) = 64 + 1.60 = 65.60
Answer:
120 books
Step-by-step explanation:
57 + 3 = 60
60 x 2 = 120