Is the order pair (3,-4) a solution of the system of linear equations x+y=1 and -6x-3y=-3

↝ A single coordinate point must make both equations true in order for the point to be a solution.

Substitute x = 3 and y = -4 in both equations.

The equation isn't true. Therefore, this isn't the solution for the system.

The equation isn't true for this one.

Conclusion ↝ The (3,-4) isn't the solution.

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer