The number of intersections of the straight line y = 3x-3 and the parabola y = x2-x + 1 is () A. 0 B. 1 C. 2 d. not sure

The number of intersections of the straight line y = 3x-3 and the parabola y = x2-x + 1 is () A. 0 B. 1 C. 2 d. not sure

∵ the intersection of straight line y = 3x-3 and parabola y = x2-x + 1 is: 3x-3 = x2-x + 1, ∵ x2-4x + 4 = 0, ∵ X1 = x2 = 2, ∵ the number of intersection of straight line y = 3x-3 and parabola y = x2-x + 1 is 1. So select B

5x-2y=1 x=7-3x

5x-2y=1
x=7-3x
4x=7
x=7/4
y=(5x-1)/2=(5×7/4-1)/2=31/4÷2=31/8

Calculation: (5x-3) (5x + 3) - 3x (3x-7)

（5x-3）（5x+3）-3x（3x-7）
=25x^2-9 -9x^2+21x
=16x^2+21x-9
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