Answer:
For the first one, C is the correct answer.
For the second one, C, B, and D are correct.
Explanation:
Hi,
For the first one, you know y = x + 3 so you can just plug that into the second equation. Here's what I mean...
3x + y = 19
Plug in x + 3 for y since you know y = x + 3...
3x + (x + 3) = 19
Solve...
4x + 3 = 19
Subtract 3 on both sides...
4x = 16
Divide by 4 on both sides...
x = 4
Now, plug in 4 in the first equation.
y = x + 3
We know x = 4...
y = 4 + 3
y = 7
We know the solution is (4,7)
For the second one...
Since the two lines never intersect (cross) then there is no solution. They are parallel to each other (meaning they're going in the same direction just don't cross) and any system that doesn't have a solution will almost always have the same slope.
Hope this helps. Let me know if you have any questions :)