Hi , can anyone help please? 7) Given triangle ABC alongside
a) Determine an expression for Angle A in terms of B and C
the answer here is A = 180° - B - C

I'm just not sure how to answer b!
b) Hence, prove that cos A = sin B sin C - cos B cos C ​

When you dilate a figure with a scale factor of 1/2, what will the dilated figure look like?                                                                                           a: the dilated figure will have side lengths that are half the length of the original side lengths.                                                                          b: the angles in the dilated figure will be half the measure of the original figure.                                                                                c: the dilated figure will have side lengths twice the length of the original.

What is the value of the rational expression below when x is equal to 4 x-12 over x-8

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