Solve these problems please?

Question

im trying but i seriously dont get this stuff.....

3 (y+5) = 8y

27 = 9(5y - 2)

210(x - 3) = 840

i did some of them but i dont understand these thanks

Answer 1

3(y+5) = 8y      Multiply each term in the parenthesis by 3;

      3y+15 = 8y      Change signs when transfering values;

      3y-8y = -15       Do this arithmetically;

      -5y = -15

        y = 3  Answer

      27 = 9(5y-2)

      27 = 45y-18

   -45y = -27-18  or  45y = 27+18

    45y = 45

       y = 45/45

       y = 1  Answer

     210(x-3) =840

     210x-630 = 840

     210x = 840+630

     210x = 1470

          x = 7  Answer

Answer 2

1. 3(y + 5) = 8y.  Use the distributive property:

3y + 15 = 8y.  Gather all y's to one side of the equation.  To do this, subtract 3y from both sides of the equation:

3y - 3y + 15 = 8y - 3y

15 = 5y.  Divide both sides by 5 to get y by itself:

15/5 = y

3 = y

2. 27 = 9(5y - 2).  Distribute:

27 = 45y - 18. Add 18 to both sides to get:

27 + 18 = 45y.

45 = 45y.  Divide both sides by 45:

45/45 = y

1 = y

3. 210(x - 3) = 840. Distribute:

210x - 630 = 840. Add 630 to both sides:

210x = 1470. Divide both sides by 210:

x = 1470/210

x = 7

Answer 3

3 (y + 5) = 8y

3y + 15 = 8y {distribute the 3}

15 = 5y {subtract 3y from both sides}

3 = y {divide both sides by 5}

27 = 9(5y - 2)

3 = 5y - 2 {divide both sides by 9}

5 = 5y {add 2 to both sides}

1 = y {divide both sides by 5}

210(x - 3) = 840

x - 3 = 4 {divide both sides by 210}

x = 7 {add 3 to both sides}

Answer 4

3(y+5)=8y

3y+15=8y

3y-3y+15=8y-3y

15=5y

3=y

27=9(5y-2)

27=45y-18

27+18=45y-18+18

45=45y

1=y

210(x-3)=840

210x-630+630-840+630

210x=1470

x=7

Answer 5

1. 3 (y+5) = 8y

3y+15 = 8y

  3y - 8y = -15

       -5y = -15

         y = 3

2. 27 = 9(5y - 2)

27 = 45y - 18

    45y = 27+18

    45y = 45

       y = 1

3.210(x - 3) = 840

210x - 630 = 840

        210x = 1470

             x = 7

Answer 6

3 (y+5) = 8y          

3y+15=8y            

15=8y-3y              

15=5y                  

3=y

27 = 9(5y - 2)        

27=45y-18            

27+18=45y          

45=45y                

1=y                      

                          

                          

210(x - 3) = 840    

210x-630=840      

210x=840+630      

210y=1470          

y=7                      

All you need to do is separate like terms. But first you need to deal with the brackets. To move one term from one side to the other, you do the opposite function to both sides.

i.e. x+8=22

so we want to move the 8 we subtract it from both sides because it is  positive on the left side. What we do to one side we must do to the other.

In the case of where it's something like 4x=16 then we want to divide bt whatever number is in front of x and once again what we do to one side we do to the other

I hope this helps but if you're still lost then try emailing me and i'll help you through it

Answer 7

1)

3(y + 5) = 8y

3*y + 3*5 = 8y

3y + 15 = 8y

3y - 8y = -15

-5y = -15

y = -15/-5

y = 3

2)

27 = 9(5y - 2)

5y - 2 = 27/9

5y - 2 = 3

5y = 3 + 2

5y = 5

y = 5/5

y = 1

3)

210(x - 3) = 840

x - 3 = 840/210

x - 3 = 4

x = 4 + 3

x = 7

Answer 8

if you have x(a+b)=x(c+d)

x(a+b)=xa+xb

and x(c+d)=xc+xd

so x(a+b)=x(c+d) becomes xa+xb=xc+xd now lets find x

adding -xa to both sides of xa+xb=xc+xd gives

-xa+xa+xb=-xa+xc+xd but -xa+xa equals 0 so

0+xb=-xa+xc+xd but 0+anynumber=anynumber so

xb=-xa+xc+xd now the same with -xb

-xb+xb=-xb-xa+xc+xd gives 0=-xb-xa+xc+xd and because

-xb-xa+xc+xd=(-xb-xa)+(xc+xd)=-(xb+xa)...

-x(b+a)+x(c+d)=x(-(b+a)+(c+d))=x(c+d-b... then

x(c+d-b-a)=0 that means that x multiplied by (c+d-b-a) is equal to 0, so either x is 0 or (c+d-b-a) is cero or both are 0. What if (c+d-b-a) is cero? then c+d-b-a=0 means c+d-b=a the same way we did before. Questions? Oh, just change x for y and a,b,c,d for 0 or any other number to make it look like your questions.

Answer 9

3(y+5)=8y

Mulitply paren by three.

3y+15=8y

Move y's to one side

-8y+3y=-15  (i skipped 3y=8y-15)

-5y=-15

divide by 5

-y=-3

y=3

27=9(5y-2)

27=45y-18

27+18=45y

45=45y

45/45=y

1=y

210x-630=840

210x=1470

x=1470/210

x=7

Answer 10

210(x - 3) = 840

x-3=840/210

x-3=4

x=3+4

x=7

do the others in the same way.