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:
"How much did Wang Yong pay each month" answer: $170
"How long did it take Wang Yong to pay back his entire debt?" answer: 50 months
-13x-12. remove the parenthesis them add the like terms.
Answer:
B
Step-by-step explanation:
Answer:
This is an identity or infinite solutions
Step-by-step explanation:
10x - 12y = 22
5x - 6y = 11
-2(5x - 6y = 11 )
-10x + 12y = -22
10x - 12y = 22
0=0
Identity solution