Question

4x+5y=27
x=26-4y

4(26-4y) + 5y = 27
104 - 16y+ 5y = 27
-21y = - 77
21y = 77
y = 77/31

Now, I’m suppose to return to the 2nd equation x=26-4y and substitute 77/31 for x, I don’t understand if the is correct way or how to get the answer for the ordered pair.

Answer 1

-16y+5y=-11y, not -21y..I think that's your mistake

Answer 2

the answer is x= -2 and y= 7, this is how its done
4(26-4y)+5= 27
104-16y+5y=27
104-11y=27
-11y=-77
y= 7
then you plug in the y for the next equation
4x+5(7)=27
4x+35=27
4x=-8
x=-2
and that's how you get your x and y i hope that helped

Answer 3

Ok, so if I use the corrected number you gave, that would make y = 7.

Returning to the 2nd equation x=26-4y and substituting x for 7.

4y = 7 - 26

still does not add up, what am I doing wrong?

Answer 4

Ana, thank you, now I understand what I was doing wrong. I couldn't figure out how to rewrite the x=26-4y equation.