If the income elasticity of demand for a good is negative, it must be

If the income elasticity of demand for a good is negative, it must be an inferior good.

Explanation:

The income elasticity of demand, in economics, measures the quantity that is demanded for a good to a change in its income. Goods whose demand falls as income rises is known as an inferior good. Such inferior goods have a "negative income elasticity of demand".

Public transportation like an "intercity bus is an example of an inferior good" or service where due to low income, the consumer has to travel by bus but if the economy grows and the consumer income increases, consumers buy cars instead of traveling by bus.

if triangle abc is congruent to triangle def, their interior angles are congruent, because congruent parts of congruent triangles are congruent (cpctc).

that means ∠d is congruent to ∠a; ∠d is equal to 8x - 2.

interior angles of all triangles add to equal 180 degrees, so you can set the sum of these interior angle values equal to 180 and solve for x.

180 = (8x - 2) + 22 + 72

180 = 8x - 2 + 22 + 72

180 = 8x + 92

88 = 8x

11 = x

x = 11