Question

*fan and medal awarded*



What is the value of the y variable in the solution to the following system of equations?
5x + 3y = 7
3x - 5y = -23
-1
1
-4
4

Answer 1

-4 is my answer

Answer 2

\[5x + 3y = 7\]\[ 3x - 5y = -23\]
multiply the first equation all the way across by 3, and the second by \(-5\)

Answer 3

oops no you are off by a minus sign

Answer 4

oh my bad

Answer 5

Auditions for a play in New York were held with 100 men and women trying out for the lead singer position. If twice the number of men less three times the number of women is equal to 20, how many men auditioned?

44

40

76

64

i searched around for this one and got 76
is that right ?

Answer 6

but im thinkin 64 now.... idk help !

Answer 7

\[15x+9y=21\]
\[-15x+25y=115\]
\[34y=136\]
\[y=136\div 34=4\]

Answer 8

thanks ! can u help with the other ? i got 64 off of basic common sence

Answer 9

yes that is right

Answer 10

cool i didnt even do real math lol

Answer 11

common sense is good

Answer 12

sure you did, it is called "thinking"

Answer 13

yeaa but im thinking it over now and it doesnt make any sence

Answer 14

ok we can use an equation if you like

Answer 15

but i didnt use equations or anything. theres a difference between math and common sence math.
yes please

Answer 16

if you put \(x\) as the number of men, and \(y\) as the number of women, then since the total is 100 you know \(x+y=100\)

Answer 17

and the second weird sentence tells you that \(2x-3y=20\)

Answer 18

so you can solve
\[x+y=100\]\[2x-3y=20\] in a couple different ways
one way is to rewrite the first one as \(y=100-x\) and then substitute in to the second equation to get
\[2x-3(100-x)=20\]

Answer 19

multiply out to get
\[2x-300+3x=20\] so
\[5x-300=20\] making
\[5x=320\] so \[x=320\div 5=64\]

Answer 20

and the 300 came from the 3(100 - x) right ?

Answer 21

yes

Answer 22

well actually it is \(-300\)

Answer 23

oh okay thanks !

Answer 24

yw