Question

solve by substitution: 2x+y=0
x-3y=-7

solve by elimination: 3x+4y=1
5x-3y=21

Answer 1

Lets do the first one

Answer 2

x-3y=-7 solve for x and tell me

Answer 3

if you could take me through step by step that would be excellent, i have no idea how to do these at all, our teacher is out on maternity leave and she should have taught us this before she left

Answer 4

yes that's what i am gonna do:)

Answer 5

x-3y=-7 solve for x and tell me

Answer 6

take the -3y on other side of the equation

Answer 7

-4y

Answer 8

Will it become x=-7+3y

Answer 9

ok

Answer 10

I mean did u get the point? or shall i explain

Answer 11

can you explain please?

Answer 12

ok no problem

Answer 13

x-3y=-7 is the equation right

Answer 14

That is given in the question

Answer 15

yes

Answer 16

By adding +3y to both sides of the (=) we get

x-3y+3y=-7+3y

Answer 17

ok that makes sense

Answer 18

Will -3y and +3y get cancelled out??

Answer 19

i would say yes

Answer 20

So,
x=-7+3y

Answer 21

Our second equation is 2x+y=0 which is given in the question

Answer 22

What is the value of x we got?

Answer 23

x=-7+3y

Answer 24

So as the question says solve by substitution (put)

Shall we put it in our new equation 2x+y=0

2(-7+3y)+y=0 <--- does that make sense?

Answer 25

ok yes substitution makes sense.

Answer 26

So,
Multiply


2*-7 + 2*3y + y = 0

Answer 27

so -14 +6y?

Answer 28

-14 + 6y + y =0
-14 + 7y =0
7y = 14 Remember that signs change when we take somethin on the other side of the equation
y = 14/7
y=2

Answer 29

ok ok starting to make more sense!

Answer 30

We got the value of y now we have to find the value of x

Answer 31

tell me any of the equations from the question

Answer 32

so we still have to figure out x for the first question?

Answer 33

yes we got the value of y

Answer 34

can we add -7+3y together?

Answer 35

to make -4y?

Answer 36

Well i don't mind teaching u but if u r completely new to this topic i would find it extremely difficult to explain u. I suggest it would be better if u ask some of your teachers or tutors because this topic ( Simultaneous equations) can't be taught through an online medium.
Did u get my point.!