Then the lowest point function value should be >: 0.
Get the lowest point at the symmetry axis, that is, when x=- 1, y=c- 1/2.
So the value range of c is (1/2, +∞). If you haven't learned infinite symbols, write C >；; 1/2 will do.
(2)y=cx+ 1 because C >；; 0, so the straight line that must pass through the first quadrant goes from the upper right to the lower left.
When x=0, it intersects the Y axis at (0, 1), so it must pass through the second quadrant.
When x=- 1/C, it intersects with the negative semi-axis of the X axis, so it must pass through the third quadrant.
That is, y=cx+ 1 passing 1, 2,3 quadrants.
Pay attention to the judgment law of straight line passing through quadrant
y=kx+b
When b=0, k>0, the straight line passes through one or three quadrants; K<0, through two or four quadrants.
B>0, k>0, a straight line passes through the first, second and third quadrants; K<0, through quadrants one, two, four.
B<0, k>0, straight line passes through quadrants 1, 3 and 4; K<0, through quadrant 234.