1: Solve for either x or y in one of the equations. So x + y = -1 is y = -x -1
2: substitute the new equation in the opposite equation. So x - (-x - 1) = 7
3: distribute the negative. X + x + 1 = 7
4: combine like terms. 2x + 1 = 7
5: solve for x. Subtract 1 on both sides. 2x = 6
6: divide by 2 to get x by itself. X = 3
7: plug the new value of x into one of the ORIGINAL equations. 3 + y = -1
8: solve for y. Subtract 3 on both sides.
Y = -4
9: the solution is written as (x,y) so the solution would be (3, -4)
Answer: AC=3.5
Solve proportionally:3 over 4 equals 1.5 over x.
3x= 6
6/3=2
X=2
2+1.5=3.5
<h3><u>Original Rate</u> <u>Unit Rate</u> </h3>
90 Miles 45 Miles
2 Hours 1 Hour
Answer: <u><em>The Train travels 45 miles in one hour.</em></u>
How i got the answer? I divied the 90 by 2 because we already know the miles/hour for 2 hours and we need 1 hour.
<em><u>Give Brainliest If You Please</u></em>
Answer:

Step-by-step explanation:
I suggest looking lessons on it online if you don't understand... It's hard to do your work especially if you don't understand it. Or if your online, go to past lessons or something.