ax+by=20
a represents how many first items you bought
x represents the cost of the first item
b represents how many second items you bought
y represents the cost of the second item
Answer:
y = -2x-7/9
Step-by-step explanation:
Slope-intercept form is y=mx+b where m is the slope and b is the y intercept. Start by solving for y.
-18x-9y=7
-9y=18x+7 (divide through by -9)
y=-2x-7/9
<h3>
Answer: 9/38</h3>
Reason:
There are 10 red cards out of 10+10 = 20 total.
10/20 = 1/2 is the probability of selecting a red card.
If the red card is not put back (i.e. "no replacement"), then the chances of getting another red card is (10-1)/(20-1) = 9/19
Multiply the two fractions mentioned to get the final answer.
(1/2)*(9/19) = (1*9)/(2*19) = 9/38
