Answer:
x= 16 and y = 9
Step-by-step explanation:
1 st equation ; x+y = 25
2 nd equation ; x- y = 7
from 1 st equation
x = 25 - y
now putting value of x in 2 nd equation
x- y = 7
25 - y-y = 7
25 -2y =7
25-7 = 2y
18 = 2y
18/2 = y
y = 9
again
putting value of y in 1 st equation
x = 25-y
x = 25-9
x= 16
The solution set is answer A.
Answer: 
Step-by-step explanation:
1. By definition, two slopes are perpendicular if their slopes are negative reciprocals of each other. So, let's find the slope of the other line.
2. The equation given in the problem is written in Point-slope form:

Where m is the slope.
3. Therefore, the slope of its perpendicular line must be:

4. You have the point (-5,7), so you can substitute it into the point-slope formula to find the equation of the new line:

5. In slope intercept form is:

Answer:
30
Step-by-step explanation:
12 is 40% of the total number of cards.
12 = 0.4x, where x is total number of cards
/0.4 /0.4
30 = x
30 cards