How do you solve this set of linear equations: 7x - 5y = 9; y = x - 17x−5y=9;y=x−1?
1 Answer
Explanation:
{(7x - 5y =9), (y = x - 1) :}
Substitute
7x - 5(x-1) = 9
Multiply out the brackets
7x - 5x + 5 = 9
Subtract
7x -5x = 4
2x = 4
x = 2
Then
y = x - 1
y = 2 - 1
y = 1
To check, substitute the answers into the first equation
7x - 5y = 9
14 - 5 = 9