6C4 = 6!/(4!2!)= 720/(2*24)=15
Answer:
D
Step-by-step explanation:
D
Remember slope is

. In the graph we can just pick two points on the line to find the rise and run between. Let's say we choose (0,3) and (1,7). Between those points there is 7-3=4 rise and 1-0=1 run. So the slope is
By if it is negative or positive
You have the ratio set up correctly:
2x+2/12 = x+3/21
Now cross multiply:
2x+2 * 12 = x+3 * 21
Simplify:
24x + 24 = 21x + 63
Subtract 24 from each side:
24x = 21x + 39
Subtract 21x from each side:
3x = 39
Divide both sides by 3:
x = 39/3
x = 13