I don't get this question, the answer is b= -4 but i don't know how to arrive at this, here is the question:
For what value of b will the line y= -2x+b be tangent to the parabola y= 3x^2+4x-1
Please show me the grade 11 way of getting this answer... last time i asked a question like this someone person gave me one complicated response that looked like a mathematician couldn't even solve so please... thanks!!!
For what value of b will the line y= -2x+b be tangent to the parabola y= 3x^2+4x-1
Please show me the grade 11 way of getting this answer... last time i asked a question like this someone person gave me one complicated response that looked like a mathematician couldn't even solve so please... thanks!!!
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The line is tangent to the parabola (i.e. the line and the parabola meet at only one point). This means that the equation -2x+b = 3x^2 +4x-1 has only one solution.
-2x+b = 3x^2+4x-1
==> 3x^2 +6x -1-b=0
For having only one solution, discriminant must be zero:
D = 6^2 - 4(3)(-1-b) = 36 +12(1+b) = 0
==> 1+b = -3 ==> b= -4
-2x+b = 3x^2+4x-1
==> 3x^2 +6x -1-b=0
For having only one solution, discriminant must be zero:
D = 6^2 - 4(3)(-1-b) = 36 +12(1+b) = 0
==> 1+b = -3 ==> b= -4