solve by elimination method
7x+15y=32
x-3y=20
To solve this system of equations by the elimination method, we need to eliminate one variable by adding or subtracting the equations.
First, let's eliminate the variable "x" by multiplying the second equation by 7:
7(x - 3y) = 7(20)
7x - 21y = 140
Now the system of equations becomes:
7x + 15y = 32
7x - 21y = 140
Next, subtract the second equation from the first equation:
(7x + 15y) - (7x - 21y) = 32 - 140
7x + 15y - 7x + 21y = -108
Simplify the equation:
36y = -108
Now, we can solve for y by dividing both sides of the equation by 36:
y = -108 / 36
y = -3
Substitute the value of y back into one of the original equations to solve for x. Let's use the second equation:
x - 3(-3) = 20
x + 9 = 20
Now, solve for x:
x = 20 - 9
x = 11
Therefore, the solution to the system of equations is x = 11 and y = -3.
Plug in 20 + 3y for x in the first equation, and solve the resulting equation for y. Here's how it starts off.
7(20+3y) + 15y = 32
140 + 21y + 15y = 32
36 y = 108
Take it from there