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Algebra 2 - F - Homework #7

Solve the following systems of equations. Graph the lines to check your
solutions. Make sure you show all the work:


1.{2x+y=2
{5x+3y − 9

2. {5x - 2y = -2
{3x + 4y − 30

3. {-x+2y =
{3x + y = 15

Please help

Algebra 2 - F - Homework #7 Solve the following systems of equations. Graph the lines-example-1

1 Answer

4 votes

{2x + y = 2

{5x + 3y - 9

Solution: We can solve this system of equations either by substitution or elimination method. Here, let's use substitution method.

From equation 1, we have: y = -2x + 2

Substituting this in equation 2, we get: 5x + 3(-2x + 2) - 9 = 0

Expanding the right-hand side, we get: 5x - 6x + 6 - 9 = 0

Simplifying further, we get: -x + (-3) = 0

Adding x to both sides, we get: -3 = x

Substituting this value of x in y = -2x + 2, we get: y = -2(-3) + 2 = 6

So, the solution to the system of equations is (x, y) = (-3, 6)

{5x - 2y = -2

{3x + 4y - 30

Solution: We can solve this system of equations by either substitution or elimination method. Here, let's use elimination method.

We can multiply equation 1 by 3 and equation 2 by 2, to make the coefficients of y same in both equations. Doing this, we get:

15x - 6y = -6

6x + 8y - 60 = 0

Adding these two equations, we get: 21x + 2y - 60 = 0

Simplifying further, we get: 21x = 60 + 2y

Dividing both sides by 21, we get: x = (60 + 2y)/21

Substituting this in equation 1, we get: 5((60 + 2y)/21) - 2y = -2

Expanding the right-hand side, we get: 60/21 + 10/21 y - 2y = -2

Simplifying further, we get: 60/21 + (-12/21) y = -2

Adding 12/21 y to both sides, we get: 60/21 = (-2) + (12/21) y

Subtracting -2 from both sides, we get: 62/21 = (12/21) y

Dividing both sides by 12/21, we get: y = 62/12 = 5 1/6

Substituting this value of y in x = (60 + 2y)/21, we get: x = (60 + 2(5 1/6))/21 = (60 + 11 1/3)/21 = (71 1/3)/21 = 71/21 + 1/63

So, the solution to the system of equations is (x, y) = (71/21 + 1/63, 5 1/6)



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