solve by the the substitution method
8x+9y=-39
pick a value for y and substitute it in to get x.
are you seriously in college? drop out lol
To solve the given equation using the substitution method, follow these steps:
Step 1: Solve one of the equations for one variable in terms of the other variable.
In this case, let's solve the first equation for x:
8x + 9y = -39
Rearrange the equation to isolate x:
8x = -9y - 39
Divide both sides of the equation by 8:
x = (-9y - 39) / 8
Step 2: Substitute the expression of x obtained from one equation into the other equation.
Now, substitute the value of x in the second equation:
4x - y = 19
Replace x with the expression (-9y - 39) / 8:
4((-9y - 39) / 8) - y = 19
Simplify further:
(-36y - 156) / 8 - y = 19
Step 3: Solve the resulting equation for the remaining variable.
Multiply both sides of the equation by 8 to eliminate the fraction:
-36y - 156 - 8y = 152
Combine like terms:
-44y - 156 = 152
Add 156 to both sides:
-44y = 152 + 156
-44y = 308
Divide both sides by -44:
y = 308 / -44
y = -7
Step 4: Substitute the value of y back into one of the original equations to solve for the other variable.
Let's substitute y = -7 into the first equation:
8x + 9(-7) = -39
8x - 63 = -39
Add 63 to both sides:
8x = -39 + 63
8x = 24
Divide both sides by 8:
x = 24 / 8
x = 3
Step 5: Check the solution by substituting the values of x and y into both original equations.
Substituting x = 3 and y = -7 into the original equations:
8(3) + 9(-7) = -39
24 - 63 = -39
-39 = -39
Therefore, the solution to the equation 8x + 9y = -39 using the substitution method is x = 3 and y = -7.