What is the result of subtracting the second equation from the first? x-3y=6 -8x-y=6

What is the quadric regression equation that fits these data

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Me solve this problem, and someone clearly explain to me how to solve it.1.) use the value of the discriminant to determine if the given trinomials has 2 real solutions, 1 real solution, or no real solutions.a.  x2  − 4x  − 7 = 0b. 4r2  + 11r  − 3 = 0c. 3m2  + 7 = 0d.  t2  + 2t  + 1 = 0