Sum of 1st cube no N th triangle no
2(x + 7) + x = 20
Distribute 2 inside the parentheses.
2x + 14 + x = 20
Combine like terms.
3x + 14 = 20
Subtract 14 from both sides.
3x = 6
Divide both sides by 3.

I thing the correct answer is C, but i'm not sure
The first answer is C and the second answer is B. The final answer is B.
Step-by-step explanation:
$68 000 × 8 years
= $544 000
$1 500 × 8 years
= $12 000
$544 000 + $12 000
= $556 00