2. find the measure of angle a.

make sure to show all work.

∠A = 80°

Step-by-step explanation:

The left vertex of the triangle = 4x - 3 ( vertical angles )

The external angle of a triangle is equal to the sum of the 2 opposite interior angles.

125° is an external angle of the triangle, thus

5x + 20 + 4x - 3 = 125, that is

9x + 17 = 125 ( subtract 17 from both sides )

9x = 108 ( divide both sides by 9 )

x = 12

Hence

∠A = 5x + 20 = (5  × 12) + 20 = 60 + 20 = 80°

all it means is function 3

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a