12x+5y+z=0 23x+4y-z=0

z=a

I know the answer is

(9a-35a,67a)

But I don’t know how to get there
We are solving with guasian

Which of these people has balanced their checkbook correctly? oa. gary: the balance in his check register is $500 and the balance in his bank statement is $500. b. gail: the balance in her check register is $400 and the balance in her bank statement is $500. c. gavin: the balance in his check register is $500 and the balance in his bank statement is $510.

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

The function f(x) is shown in this graph the function g(x)=6x