The difference is -10 because
9-10= 1
-1-10= -11
-11-10= -21
common difference means you add and common ratios means you multiply.
hope this helps!
The answer should be b¹². You add the exponents of each constant. In the case of the simple b the exponent would be one.
y² = 8y - 15 (alternate angles are equal)
y² - 8y + 15 = 0
(y - 5)(y - 3) = 0
y = 5 or 3
x + 8y - 15 = 180 (angles in a straight line add up to 180)
when y = 5
x + 40 - 15 = 180
x = 155°
when y = 3
x + 24 - 15 = 180
x = 171°
