First, you combine like terms. I would start by circling the term and the sign in front of it. (A term is a piece separated by an addition/subtraction sign.) You can only combine terms with the same variable. 4.8a-2.1a-6.3b+7b is the same as your equation, just rearranged. Then, subtract (4.8a-2.1a) which is 2.7a. Add (-6.3b to 7b) The answer is 0.7b. If you have any questions, you can message me!
You can tell if the equation is linear or not if the equation makes a straight line on a graph.
Let x be the expected number
Number arriving = 3•5 x
Unexpected number 2•5 x
2•5 x = 105
10x = 420
x = 42______Option D
Based on your problem, you only have one given. So, you can't make an equation for this because there are not limits to the equation. The only thing that you know is that the three numbers are consecutive even integers. My way of solution for this is trial-and-error. However, it's really quite easy.
For example: 42 + 46 = 88. I have to increase the numbers more to reach 136. Suppose: 82 + 86 = 168. That exceeded 136. So, it must be between 46 and 82. Suppose again: 66 + 70 = 136. Therefore, the sequence of the consecutive even integers are 66, 68, and 70.