Line d and c are bother parallel but the three options would be them
The surface in medium is connected to both y and e
Answer: He'd have to work 15 days.
Step-by-step explanation
With the money in his bank account he'd have to get $173 to be able to pay for the rest of the board. If you were to divide 173 by 12 you'd get 14.4166666667. But you can't have a decimal so you'd round up to get a total of 180. Which is how you get the answer of him needing to work for 15 days.
1.) The sum(addition) of 21 and 5 times(multiplication) a number f is(=) 61.
f = unknown number/variable [So 21 plus 5f(5 times f) equals 61]
21 + 5f = 61 [21(one-time) + 5f(number x variable) = 61(total)]
2.) Seventeen more(addition) than seven times(multiplication) a number j is(=) 87.
j = unknown number/variable [So 17 plus 7j(7 times j) equals 87]
17 + 7j = 87
3.) n = number of calls
18 + 0.05n = 50.50
[Company charges $18 plus five cents per call(n), and the total charge was $50.50]
4.) s = the number of students
40 + 30s = 220
[Tutor charges $40 plus $30 per student(s), and the total charge was $220]
<span>5x + 20 = -5x
5x + 5x = -20
10x = -20
x = -20/10
x = -2</span>