Question

I need help with two math problems. I have tried working them out many times myself. and keep getting the wrong answer.
System of equations: solve by addition.

1: .2x - .5y = -.4
-.3x + .4y = -.1
solution = (3,2)

2: 1/2x - 1/3y = 1
1/4x - 1/9y = 2/3
solution = (4,3)

please explain what you are doing, I am only asking for help so i can pass my test.

Answer 1

all I can say is use guess and check sorry if it's not that helpful but that's what I do when idk what to do

Answer 2

you said you tried solving it. can i see your solution so that we can find what you did wrong?

Answer 3

these are my last attempts for these two problems

Answer 4

ok it seems the decimals threw you off a bit for #1
and you did more work than you need to

why dont i just post a solution with explanation

first of i would get rid of decimals by multiplying everything by 10
2x - 5y = -4
-3x +4y = -1

Now instead of adding them right away, you want to change the coefficients so that a variable is eliminated after adding
Lets eliminate the "x" , 2 and 3 have common multiple of 6
multiply first equation by 3, 2nd equation by 2

6x - 15y = -12
-6x + 8y = -2
-----------------------
0 -7y = -14

solve for y

y = -14/-7 = 2

Answer 5

plugging y back in

--> 2x - 5(2) = -4

2x -10 = -4

2x = 6

x = 3

Answer 6

That makes sense to me.

Answer 7

good

for #2 , you can also get rid of fractions by multiplying by a common denominator
4 and 9 have common multiple of 36 --> multiply everything by 36

18x - 12y = 36
9x - 4y = 24

Answer 8

try to do rest on your own

Answer 9

here is a video to help explain how to solve system of equations

https://www.khanacademy.org/math/algebra2/systems_eq_ineq/systems_tutorial_precalc/v/systems-with-elimination-practice

Answer 10

gotta go, good luck :)

Answer 11

thank you so much. i appreciate it. and I think i got it this time.