A curve is given by x = 2t + 3, y = t

3 − 4t, where t is a parameter. The point A

has parameter t = − 1 and the line l is the tangent to C at A. The line l also cuts

the curve at B.

(a) Show that an equation for l is 2y + x = 7.

(b) Find the value of t at B.