Question

what's the best way to solve this system of equations?

Answer 1

5x + 3y = 46
2x + 5y = 7

Answer 2

I'd use elimination

Answer 3

every time i try to use elimination it turns out with numbers that are none of my choices

Answer 4

Let's do it by sustitution:
5x + 3y = 46
2x + 5y = 7
Let's pick a equation and solve it for y:
\[5x+3y=46\]
Then:
\[y=\frac{ 46-5x }{ 3 }\]
And let's substitute in the other equation:
\[2x+5(\frac{ 46-5x }{ 3 })=7\]
try solving that equation for x.

Answer 5

solution should not depend on the method u use to solve it

Answer 6

Sometimes one method is more convinient to use than an other.

Answer 7

yup ^

Answer 8

i literally don't even know how to solve that equation..

Answer 9

can you walk me through it

Answer 10

to solve x, u must isolate x

Answer 11

FYI, the answer has to be one of these 4 things

(2, 10)

(3, 4)

(3, 11)

(11, -3)

Answer 12

\(\large \begin{array}{llrrrr}
5x + 3y = 46 & \times 2 \implies &10x &+ 6y &= &92\\
2x + 5y = 7 & \times -5 \implies &-10x &+ -25y &= &-35
\end{array}\)

Answer 13

lets start wid a simple thing,
x+3 = 7

u can solve this, eh ?

Answer 14

x = 4

Answer 15

thats all it needs to solve anything

Answer 16

... still don't know how to do it with that fraction

Answer 17

lets take another example, before doing the actual problem

\(\large x + \frac{3}{19} = 10\)

can u solve this ?

Answer 18

x = 10 - 3/19

Answer 19

Awesome !


\(\large 2x+5(\frac{ 46-5x }{ 3 })=7 \)

Answer 20

i do not know how to do that like seriously

Answer 21

you refering to this equation, right ?

Answer 22

yes

Answer 23

first observe that x is not isolated yet,

Answer 24

\(\large \begin{array}{llrrrrll}
5x + 3y = 46 & \times 2 \implies &10x &+ 6y &= &92\\
2x + 5y = 7 & \times -5 \implies &-10x &+ -25y &= &-35\\
\hline
&&0&-19y& = & 57&\\\implies y = -\cfrac{57}{19} = 3
\end{array}\)

Answer 25

\(\large 2\color{red}{x}+5(\frac{ 46-5\color{red}{x} }{ 3 })=7 \)

Answer 26

should be the same using substitution though

Answer 27

jdoe0001 why is there an = 3 on the end of that

Answer 28

ok lets wait for jdoe to finish, we can continue after that

Answer 29

ohh hamme. -3 rather

Answer 30

\(\large \begin{array}{llrrrrll}
5x + 3y = 46 & \times 2 \implies &10x &+ 6y &= &92\\
2x + 5y = 7 & \times -5 \implies &-10x &+ -25y &= &-35\\
\hline
&&0&-19y& = & 57&\\
\implies y = -\cfrac{57}{19} = -3
\end{array}\)

Answer 31

look i really don't know how to isolate the x with that fraction like i really don't. like i don't understand any probably never will so i'm giving up on that method. i understand that i'm supposed to isolate the x but i don't know how to frickin do it on that type of problem. i'm sorry. it just doesn't click.

Answer 32

x is 11 y is -3. got it. thank you both

Answer 33

if u dont want to learn its fine :)
i thought you're struggling, and trying to understand it

Answer 34

i am struggling and i need help but i just suck at math.