A
given the 2 equations
2x + y = - 2 → (1)
x + y = 5 → (2)
subtract (2) from (1) term by term to eliminate y
(2x - x ) + (y - y ) = (- 2 - 5 )
x + 0 = - 7 ⇒ x = - 7
substitute x = - 7 in either of the 2 equations and solve for y
(2) : - 7 + y = 5 ( add 7 to both sides )
y = 5 + 7 = 12 → A
I think B should be the top one
Answer: Leanna ran 39.96 miles before she was passed by Irina.
Step-by-step explanation:
When Irina would pass Leanna, they would have ran the same distance.
Let t represent the time that Leanna ran before she was passed by Irina.
Distance = speed × time
Leanna started in group E and ran at a rate of 4.8 miles per hour. The distance ran by Leanna before she was passed by Irina is
4.8 × t = 4.8t
During the race she was passed by Irina who ran at a rate of 5 miles per hour and started in group H, 20 minutes(20/60 = 0.333 hour) after Leanna started. The time spent by Irina in running this distance is
t - 0.333
Distance ran by Irina is
5(t - 0.333) = 5t - 1.665
Since they ran the same distance, then
4.8t = 5t - 1.665
5t - 4.8t = 1.665
0.2t = 1.665
t = 1.665/0.2 = 8.325 hours
Therefore, the distance that Leanna ran before she was passed by Irina is
4.8 × 8.325 = 39.96 miles
I dont know, but someone ate my lefts overs >:(
Answer:
Step-by-step explanation:
Remark
Always the easiest way to study these questions is to get a graph. The one below shows
Red: y = x^2
Blue: y= 3(x + 1)^2
You will notice that (x+1)^2 shifts the graph Left -- the opposite to what you might think.
The 3 is a little harder. It narrows the red mother graph. Which choice says that?
The choice is between b and d. Why. Because the blue graph is to the left of the red one.
You have to learn the meaning of compressed. A better word might be narrows.
Answer
B
