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Solve by Addition/Elimination "{9x - 5y = -30 {x + 3y = 18 (put both into graph, find where they both cross the point)"

asked
User AKun
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1 Answer

4 votes

Answer:

Explanation:

To solve the system of linear equations using the addition/elimination method, you can manipulate the equations to eliminate one of the variables. Here's how you can do it:

Start with the original equations:

9x - 5y = -30 ...(1)

x + 3y = 18 ...(2)

To eliminate one of the variables, let's eliminate "x." Multiply equation (2) by 9 so that the coefficients of "x" in both equations become equal:

9(x + 3y) = 9(18)

This simplifies to:

9x + 27y = 162 ...(3)

Now, you have the modified equation (3) and the original equation (1). You can subtract equation (1) from equation (3) to eliminate "x":

(9x + 27y) - (9x - 5y) = 162 - (-30)

9x + 27y - 9x + 5y = 162 + 30

Combine like terms:

32y = 192

Divide by 32 to solve for "y":

y = 192 / 32

y = 6

Now that you have the value of "y," you can substitute it into equation (2) to solve for "x":

x + 3y = 18

x + 3(6) = 18

x + 18 = 18

Subtract 18 from both sides:

x = 0

So, the solution to the system of equations is:

x = 0

y = 6

Now, you can graphically represent this solution by plotting the point (0, 6) on a coordinate plane. This is the point where the two lines representing the equations intersect.

Here's how the equations look when graphed:

Equation (1): 9x - 5y = -30

Equation (2): x + 3y = 18

The point of intersection is (0, 6).

answered
User Andrey Frolov
by
8.3k points

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