8. combine the like terms in this expression: –3x + 2xy + 4y – xy + 2x – 11y a. 23x + y b. 2xy + 15 c. –7xy d. –x+xy–7y

D. –X+XY–7y

Step-by-step explanation:

We just have to combine (add) the similar terms... so all terms that have an x in them for example.

–3x + 2xy + 4y – xy + 2x – 11y

Let's first re-write it placing similar terms next to each other

(-3x + 2x) + (2xy - xy) + (4y - 11y)

Then we sum them up, for each similar terms

1x + 1xy -7y

so, x + xy -7y

Answer D.

(a) {a₁, a₁r, a₁r², … a₁rⁿ⁻¹, …}

(b) $59 398

step-by-step explanation:

(a) the annual sequence of profits

aₙ = a₁rⁿ⁻¹

the model for the sequence of profits is {a₁, a₁r, a₁r², … a₁rⁿ⁻¹, …} .

(b) profit after 15 yr

  a₁ = $ 30 000

  r = 1.05

a₁₅ = 30 000 × 1.05¹⁴

a₁₅ = 30 000 × 1.979 93

a₁₅ = $59 398

the profit in year 15 will be $59 398.