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If a is 0 and B is 0, what is the symbol of 2a-3b?
2a-3b=2a+3(-b)
a> 0, 2A > 0
b0
That is 2A + 3 (- b) > 0
So the sign 2a-3b > 0 is positive
The image of quadratic function y = ax & sup2; + BX + C is shown in the figure, and P = | a + B + C | + | 2A + B |, q = | a + B + C | + | 2a-b |
I can't upload the graph. The function passes through the origin, the axis of symmetry is greater than 1, the opening is downward, and the vertex coordinates are in the first quadrant
What is the image like?
The image must have information about a, B, C
It is known that the image opening of quadratic function is downward and passes through the origin______ ．
The opening of the image of the quadratic function is downward, a ＜ 0, the image of the quadratic function passes through the origin, C = 0. So the analytic formula can satisfy a ＜ 0, C = 0, such as y = - x2
The image of quadratic function passes through the parabola of three points a (4,0) B (0, - 4) C (2, - 4), and the analytic expression of the function is obtained
y=ax^2+bx+c
B（0,-4） c=0
A（4,0） 0=16a+4b 4a+b=0
C（2,-4） -4=4a+2b 2a+b=-2
a=1 b=-4
The analytic expression of function y = x ^ 2-4x
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