You will need about 3 4ths
Equating the y's:-
3x + c = x^2 - 5x + 7
x^2 - 8x +7 - c = 0
If y = 3x + c is a tangent then there will be duplicate solutions to this equation
That is the discriminant b^2 - 4ac = 0. So we have:-
(-8)^2 - 4 * 1 * (7 -c) = 0
64 -28 + 4c = 0
4c = - 36
so c = -9 answer
48 degrees that is the answer
5x²+13x-4-17x²-7x+19+15x²+5x-21x-7=
=5x²+15x²-17x² +(13x-7x+5x-21x) -4-7+19=
=3x²-10x+8
3/4 is .75 so you do .75 multyplyed by 6 and get 4 1/2. Hope I helped!