Select all of the given trigonometric equations that are true statements. sin(180°) = cos(0°) cos(74°) = sin(16°) sin(20°) = cos(70°) sin(A°) = cos(90° - A°) sin(A°) = cos(180° - A°) cos(140°) = sin(40°)

Cos 74°= Sin 16°

Sin 20°= Cos 70°

Sin A°=Cos (90°- A°)

Step-by-step explanation:

This is because the three pairs are complementary i.e they add up to 90° and in trigonometric ratios, complementary ratios are equal.

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -