Answer:
3) no solutions
4a) x=-9 and y=-3 or (-9,-3)
4b) x=4 and y=-6 or (4,-6)
4c) x=13 and y=-9 or (13,-9)
Step-by-step explanation:
For #3, both expressions are equal to y, so we set them equal to each other and solve:
-x+4=-x+2
-x=-x-2
0=-2
Looks like number 3 has no solution. You can also tell they have no solution because both expressions have the same slope but different y-intercept, meaning they'll never intersect.
For #4a, we already have the value of x, so we plug in to the top equation and solve for y then get x from y:
2y+3y=-15
5y=-15
y=-3
Since x=3y, then x=3(-3) which is x=-9. So your answer is x=-9 and y=-3 or (-9,-3) as an ordered pair.
For #4b, we can use elimination to cancel the "y"s out and solve for x then use that to get y:
5x=20
x=4
Since 2x+y=2, then 2(4)+y=2 which is 8+y=2 which is y=-6. So your answer is x=4 and y=-6 or (4,-6) as an ordered pair.
For #4c, we can use elimination to cancel the "5x"s out and solve for y then use that to get x:
4y=-36
y=-9
Since 5x+7y=2, then 5x+7(-9)=2 which is 5x-63=2 which is 5x=65 which is x=13. So your answer is x=13 and y=-9 or (13,-9) as an ordered pair.
