Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

The correct answer is Option C

Step-by-step explanation:

In this question first we use the sum and difference formula :

cos (a-b) = cos(a) cos(b) + sin (a) sin (b)

Let a = 180 and b = q, then

cos (180-q) = cos (180) cos (q) + sin (180) sin (q)

Now the sin of 180 degree is 0. Since 0 multiplying  with anything leaves 0, this makes sin (180) sin (q) = 0

cos (180-q) = cos (180) cos(q)

Now the cos of 180 degree is -1.

cos(180-q) = -1 cos(q), or cos (180-q) = -cos(q)

i believe it is c.y = 9x

rise over run. 9 units up over 1 unit right or 9/1

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.