# How do you solve #3x+y=0# and #5x+y=4#?

##### 3 Answers

#### Answer:

#### Explanation:

You can solve the first equation for

So, let's do it in the second: instead of

We can sum the terms in the left hand side to get

And finally solve for

Now that we know that

#### Answer:

#### Explanation:

#3x+y=0to(1)#

#5x+y=4to(2)#

#"from equation "(1)color(white)(x)y=-3xto(3)#

#"substitute "y=-3x" into equation "(2)#

#5x-3x=4rArr2x=4rArrx=2#

#"substitute "x=2" into equation "(3)#

#y=-3xx2=-6#

#"point of intersection "=(2,-6)#

graph{(y+3x)(y+5x-4)=0 [-16.02, 16.02, -8, 8.02]}

#### Answer:

#### Explanation:

Let ,

From

Subst .

From

Hence,