If ∠c and ∠d are vertical angles and m∠c=x and m∠d=−3x+80, what is m∠c?

i'm super lost, can someone ?

Cameron made 1 loaf of bread. his family ate 4/6 of the loaf of bread. how much of the loaf of bread remains? /

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11

Ireally need subtract and simplify.(-y^2 – 4y - 8) – (-4y^2 – 6y + 3)show your work, ! i will mark you brainliest but you have to show your work.