solve by substitution method:
9x+7y=4
x=23-4y
just plug in the x value in the x in the first eqaution and solve
To solve the system of equations by the substitution method, you will substitute the value of one variable from one equation into the other equation. Let's solve this system step by step:
Given equations:
1) 9x + 7y = 4
2) x = 23 - 4y
We can start by substituting the value of x from equation (2) into equation (1). Since x = 23 - 4y, we can rewrite equation (1) as:
9(23 - 4y) + 7y = 4
Now, we solve this equation to find the value of y.
Distribute 9 to the terms inside the parentheses:
207 - 36y + 7y = 4
Combine like terms:
-29y + 207 = 4
Subtract 207 from both sides of the equation:
-29y = 4 - 207
Simplify:
-29y = -203
Divide both sides of the equation by -29:
y = (-203) / (-29)
y = 7
Now that we have the value of y, we can substitute it back into either equation (1) or (2) to find the value of x. Let's use equation (2):
x = 23 - 4y
x = 23 - 4(7)
x = 23 - 28
x = -5
Therefore, the solution to the system of equations is x = -5 and y = 7.