The average number is 85. if three of the numbers are76,78,81 what is the forth number

105

Step-by-step explanation:

The formula for finding average, a.k.a. mean, is the sum of the terms divided by the number of terms. So to find the 4th number, you need to do 85x4 first, to get 340, which is the sum of the terms(specifically 76, 78, 81, and the unknown number). 76+78+81=235. 340-235=105, therefore 105 is the fourth number.

the answer

b. they are parallel and will never intersect.

step-by-step explanation:

ok so im not 100% sure but you would start by adding 5.1t and 1.9t beacuse they have the same variable. that is 7t.   then add -3.6 + 1.2 which is -2.4

so then keep that as -2.4 + 7t. i apologize if this is incorrect. best luck on your test < 3