The first one is B and the second is D
Graph A.....parallel lines will have no solution because they never intersect
Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
= (2sin20°cos20°)cos40°cos80°
= (2sin40°cos40°)cos80°
= (sin80°cos80° )
= (2sin80°cos80° )
= . sin160°
= . sin(180 - 20)°
= . sin20°
= = right side , thus proven
This would just be 7 1/5 + 3/5 since the negative sign gets distributed and makes (-3/5) into a positive number.
From there you have basic math and you get 7 4/5.