How do you use the substitution method to solve the system of equations 4x + y = 3 and 7x + 9y = 2?

To solve the system of equations using the substitution method, we’ll first rewrite one of the equations to express one variable in terms of the other.

Let’s take the first equation:

4x + y = 3

We can isolate y:

y = 3 - 4x

Now we have y expressed in terms of x. Next, we will substitute this expression for y into the second equation:

7x + 9y = 2

Substituting the expression we found:

7x + 9(3 - 4x) = 2

Now, expand and simplify this equation:

7x + 27 - 36x = 2

Combine the x terms:

-29x + 27 = 2

Next, isolate x:

-29x = 2 - 27
-29x = -25
x = -25 / -29
x = 25/29

Now that we have the value of x, we can substitute this value back into the equation we found for y:

y = 3 - 4(25/29)

Calculating y:

y = 3 - 100/29
y = (87/29) - (100/29)
y = -13/29

So, the solution to the system of equations is:

(x, y) = (25/29, -13/29)

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