Question

I just can't solve these three problems! : ( I am isolating the x first, then substituting the x into the second part, but then I get mixed up on what to do next. Any help or hints are appreciated!!

Use the substitution to solve this system of equations.

7. {y+2x=11
{x+y=5

10. {3x +y =-4
{1/2x+y =6

11. {x+2y=2
{2x+3y=-1

Thank you!

Answer 1

which one were you solving?

Answer 2

I was attempting to solve all three of those. :/

Answer 3

hmm

for 1. you have x = 5 - y <--sub that into the first equation

2. isolating x is not easy here so it's preferrable to use y.
y = -4 - 3x <--sub that into the second equation

3. x = 2 - 2y <--sub that into the second equation

remember to always find the easy way out. don't stick too much to the rules

Answer 4

Oh! Great. Let me try that and post my answers. =)

Answer 5

sure

Answer 6

2y = 11/5 is what I have so far

Is that okay? Then I would isolate the y by dividing 2, correct? I'm sorry, math is my worst...

Answer 7

which number is this?

Answer 8

The first one =)

Answer 9

Sorry!! Woops I just saw my mistake!! Ahhh

Answer 10

nice. i was about to point it out

Answer 11

Okie dokie I got y=-1
fingers crossed! I would then use that y and input it into an original equation to get x right?

Answer 12

x = 5 - y

y + 2(5-y) = 11
y + 10 - 2y = 11
-y = 1
so y = -1 right

Answer 13

Yay! Awesome

Answer 14

yes to your second question too

Answer 15

Okie dokes. Can I input y to any of the two equations?

Answer 16

yes

Answer 17

x=6

Answer 18

right

Answer 19

Wow thanks!!! I should be fine on the other two problems!

Thank you very much!