We can solve this system of equations by elimination. 

By adding the second equation to the first, we get  or .

Substitute y=-4 into either equation and solve for x. 

Simplify and solve for x to get .

Therefore, the solution to this system of equations as an ordered pair is (7, -4). 

We can express this problem as a system of equations where s represents scones and d represents donuts. 

We can solve this system of equations by elimination as follows:

Subtracting the second equation from the first yields  or . 

Therefore, donuts cost $2. 

We can express the given information as a system of equations. Let L represent the votes cast for Lisa, and let J represent the votes cast for Jon. 

The total votes cast in the election can be written as

Since Lisa received 50 more votes than Jon, we can write

We can solve this system of equations by substitution.

Let's rewrite the second equation in terms of J. 

.

Now, we can substitute  into .

This gives us

We can simplify this to get .

To calculate the percentage of the votes that were cast for Lisa, we take her 150 votes and divide them by the total number of votes cast in the election. Then, we multiply that by 100%.

0.6 x 100% = 60%

Any time the product of consecutive numbers is , must be a one of those consecutive numbers, because if it is not, the product will be non-zero. This leaves us with four possibilities, depending on where  is placed in the sequence.

As we can see, , , and are our numbers in question, meaning is our answer as the lowest number.

Note that it is possible to use algebra and set up a system of equations, but it's more time-consuming, which could hinder more than help in a standardized test setting.

If we use elimination to solve this system of equations, we can add the two equations together. This results in 0=0. 

When elimination results in 0=0, that means that the two equations represent the same line. Therefore, there are an infinite number of solutions. 

We can solve this system of equations by elimination since the 2 given y-values have the same coefficient. Let's subtract the second equation from the first.

This gives us  or .

Substitute this x-value into either equation and solve for y. Let's use the first equation like so:

The solution is .

We can solve this problem by elimination. 

Subtract the second equation from the first to eliminate the x values, like so:

This yields

Now, substitute  into either equation and solve for x. In either equation, we find that . 

Therefore, the solution to this system of equations is .

To solve this problem, we can set up a system of equations. 

Let  represent the cost of donuts, and let  represent the cost of a cup of coffee. 

We can write Giovanni and Jalynn's purchases as equations like this:

To solve this system of equations, we can use elimination by subtracting the second equation from the first, like so:

Our  terms drop out, leaving us with

Therefore, each cup of coffee costs . 

Because the coefficients of the  values are the same, we can solve this problem by elimination. Subtract the second equation from the first:

This knocks out our  value and gives us , or .

Then, substitute this value into either of the equations to solve for . Let's use the second equation:

Therefore, the solution is 

Since none of our coefficients are the same, we cannot solve by elimination. Therefore, we'll use substitution. Let's solve for one term in one equation. 

Now, we can substitute this expression into the second equation.

Now, we can substitute this value back into either of the original equations to find our solution. Let's use the simplest equation:

With these values, we see that our solution is the point .