**Answer:**

**Step-by-step explanation:**

Fire house Light = 90

30=30-90

Answer:

D

Step-by-step explanation:

**Answer:**

**A proportional relationship is there.**

**Step-by-step explanation:**

**Here in the table, the values of y are given corresponding to the values of x.
**

There are four sets of values of x and y.

We have to check whether the relationship is proportional or not.

**Now, rate of change of y with respect to x will be from the first two pair of values is =
**

**Again, rate of change of y with respect to x will be from the second two pair of values is =
**

**And, rate of change of y with respect to x will be from the third two pair of values is =
**

**So, the rate is always 0.75.
**

**Therefore, a proportional relationship is there. (Answer)**

**Answer:**

guess and check

**Step-by-step explanation:**

Linear equation systems usually have two or more variables to find.

The values for these variables can be found by different methods, some of them are indeed graphing, substitution and with matrices.

So these are correct options that are used to solve linear systems of equations.

On the other hand,** the guess and check method is not used to find the solution of these systems**, since the more variables the system has the more difficult it is to guess the answer,<u> the graphic and mathematical methods are more effective and reliable.</u>