Jika garis y = x - ¾ menyinggung parabola y = m - 2x - x², maka m sama dengan A. -3 B. -2 C. 0 D. 2 E. 3

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y1 = x- 3/4
y2 =m - 2x - x²
y1 - y2 = 0
x- 3/4 = m - 2x - x²
x² + x + 2x - 3/4 - m = 0
x² + 3x + (- 3/4 - m) =0
a= 1, b = 3, c= -3/4 - m
menyingung D = 0
b²-4ac = 0
3² - 4(1)(-3/4 - m)= 0
9 + 3+ 4m= 0
12+ 4m= 0
4m = -12
m =-12/4
m = - 3