Answer:
[tex]\text{C. }(5,2)[/tex]
Step-by-step explanation:
The x-coordinate vertex of a parabola in standard form [tex]ax^2+bx+c[/tex] is equal [tex]\frac{-b}{2a}[/tex].
In [tex]y=3x^2-30x+77[/tex], we have:
- [tex]a[/tex] equals 3
- [tex]b[/tex] equals -30
Therefore, the x-coordinate of the vertex is equal to [tex]\frac{-(-30)}{2(3)}=\frac{30}{6}=5[/tex].
To find the y-coordinate, simply substitute [tex]x=5[/tex] into the parabola's equation:
[tex]y=3x^2-30x+77,\\y=3(5^2)-30(5)+77,\\y=75-150+77,\\y=-75+77=2[/tex]
Thus, the vertex of the parabola is [tex]\boxed{(5,2)}[/tex]
