Question 239735
5x - 6x = -17
3x - 4y + 5z = -1
2z = -6


looks like you have 3 equations that have to be solved simultaneously.


looks like your third equation has already solved for z so we can start there.


2z = -6 becomes z = -3 when you divided both sides of the equation by 2.


z = -3 is the value of one of your variables.


you are left with:


5x - 6x = -17
3x - 4y + 5z = -1


that first equation looks like it's all in x so we can solve for x from that equation.


5x - 6x = -17 becomes -x = -17 after you combine like terms.


multiply both sides of this equation by -1 to get:


x = 17


you now have two values out of the 3.


you have:


x = 17
z = -3


you have only one equation left to solve.


that is:


3x - 4y + 5z = -1


replace x with 17 and z with -3 in that equation to get:


3*(17) - 4*y + 5*(-3) = -1


this becomes:


51 - 4*y - 15 = -1


combine like terms to get:


36 - 4*y = -1


add 4*y to both sides of the equation and add 1 to both sides of the equation to get:


36 + 1 = 4*y


combine like terms to get:


37 = 4*y


divide both sides of the equation by 4 to get:


9.25 = y


this is the same as:


y = 9.25


the answer to your equation is:


x = 17
y = 9.25
z = -3


substitute in your original equations to confirm these answers are good.


5x - 6x = -17
3x - 4y + 5z = -1
2z = -6


these become:


5*(17) - 6*(17) = -17
3*(17) - 4*(9.25) + 5*(-3) = -1
2*(-3) = -6


simplify and combine like terms to get:


-17 = -17
51 - 37 - 15 = -1
-6 = -6


simplify further to get:


-17 = -17
-1 = -1
-6 = -6


all equations confirm so the answer is good.