2 questions:

1. Find "a" if (-3,7) is a solution of 2x+ay=26

2. solve system using substitution, linear combination, and graphing:

3x-2y=3
5x+4y=16

1. To find the value of "a" if (-3, 7) is a solution of 2x + ay = 26, we can substitute the given values into the equation and solve for "a".

So, let's substitute x = -3, y = 7 into the equation:
2(-3) + a(7) = 26

Simplifying this equation:
-6 + 7a = 26

Next, solve for "a" by isolating the variable:
7a = 26 + 6
7a = 32

Finally, divide both sides of the equation by 7 to solve for "a":
a = 32/7

Therefore, the value of "a" is 32/7.

2. To solve the system of equations using substitution, linear combination, and graphing, let's go through each method step by step:

Substitution method:
Step 1: Choose either of the equations and solve it for one variable in terms of the other variable.
Let's solve the first equation, 3x - 2y = 3, for x:
3x = 2y + 3
x = (2y + 3)/3

Step 2: Substitute the expression obtained in Step 1 into the other equation.
Substituting x in the second equation with the expression we obtained:
5((2y + 3)/3) + 4y = 16

Step 3: Simplify the equation and solve for the remaining variable.
Multiply both sides by 3 to eliminate the fraction:
5(2y + 3) + 12y = 48
10y + 15 + 12y = 48
22y + 15 = 48
22y = 48 - 15
22y = 33
y = 33/22
y = 3/2

Step 4: Substitute the value of y back into any of the original equations to find x.
Let's substitute y = 3/2 into the first equation:
3x - 2(3/2) = 3
3x - 3 = 3
3x = 6
x = 6/3
x = 2

Therefore, the solution to the system of equations using the substitution method is x = 2 and y = 3/2.

Linear combination (elimination) method:
Step 1: Multiply one or both of the equations by appropriate numbers to make the coefficients of one of the variables in the two equations equal.
To eliminate the y variable, we'll multiply the first equation by 4 and the second equation by 2:
4(3x - 2y) = 4(3)
2(5x + 4y) = 2(16)
12x - 8y = 12
10x + 8y = 32

Step 2: Add or subtract the new equations to eliminate one variable and solve for the other variable.
Adding the two equations:
(12x - 8y) + (10x + 8y) = 12 + 32
22x = 44
x = 44/22
x = 2

Step 3: Substitute the value of x back into one of the original equations to find y.
We can substitute x = 2 into the first equation:
3(2) - 2y = 3
6 - 2y = 3
-2y = 3 - 6
-2y = -3
y = -3/-2
y = 3/2

Therefore, the solution to the system of equations using the linear combination method is x = 2 and y = 3/2.

Graphing method:
Step 1: Graph both equations on the same coordinate system.

The graph would show two lines intersecting at a point.

Step 2: Identify the coordinates of the point where the lines intersect.

The coordinates of the point where the lines intersect would be the solution to the system of equations.

Therefore, by visually examining the graph, you can determine the coordinates of the intersection point, which will give you the values of x and y.

In this case, the solution to the system of equations using the graphing method is x = 2 and y = 3/2.

I hope this helps! Let me know if you have any further questions.