Help- Linear equations for homework I'm clueless! Do you Know how?

bobsa1

Desperate mum here. DD has got linear equations for homework & the example and teacher explanations aren't helping!

first question is 16-4(x+3)=2x

I know that this means 16-4*x+3*1=2x (*denotes multiply)

but have no idea how to work it out.

Second question is 5x-2(3x+1)=-6

third Question 4x-2=1-(2x+3)

Fourth Question 4=5x-2(x+4)

Fifth Question 9x-7(x-1)=0

If anyone can help me calculate these or tell me how,I would be very grateful!

isualive

http://www.freemathhelp.com/systems-linear-equations.html

Hope this site helps.

vtmil

16 - 4x +12 = 2x Times the bracket by the 4 on the outside
16 - 12 = 6x takeaway the 4x on both sides
4 = 6x do the minus sums
x = 4/6 divide both sides by 6
Simpifys to x = 2/3

vtmil

i think - ill do the rest but it might take me some time

kay74

Hope this is right, but been a long time so feel free to shout if wrong!

16-4(x+3)=2x
= 16-4x-12=2x
= 16-12 = 2x+4x
= 4=6x
so x=2/3 (two thirds)


then 5x-2(3x+1) = 6
= 5x-6x-2=6
= -x-2=6
so -x=8 or x= -8

then 4x-2=1-(2x+3)
= 4x-2= 1-2x-3
=4x+2x=1-3+2
so 6x = 0 so x=0

then 4=5x_2(x+4)
= 4=5x - 2x-8
so 4+8 =3x
so 12=3x, x=4

lastly 9x-7(x-1)=0
= 9x-7x+7 = 0
so 2x = -7 so x= -3.5


Am I right? Heck, I hope so. Would prove some of brain still works. Hope my working helps!

vtmil

5x-2(3x+1)=-6
5x - 6x - 2 = -6
-1x -2 = -6
-1x = -4
x=4 (ive just swapped them around to make them positive and 1x is the same as x)

vij1366

try this one this shows how to work it all out but it costs about 23 pounds

http://www.algebra-help.com/g2-linear-equation.htmlhttp://www.mathsisfun.com/algebra/definitions.html

bobsa1

Vtmil- your explanations are making perfect sense to dd, so please keep going!

Kay 74 thanks so much!

kay74

oops! I've copied second sum down wrong!
Hee hee! This is just like school
should be
5x-2(3x+1) = -6
5x-6x-2 = -6
-x = -4 so x=4

Sorry!

vtmil

kay has got them right apart from question 2 - i think mine is right because it was -6x not 6x - i might be wrong tho
Just remember to times the number on the outside of the bracket by whats inside, including the + or - before it so if its 2x + 4(3x +2) then times the 3x and 2 by 4, but if it was -4 then times it all by minus 4

- x - = +
- x + = -
+ x + = + (x here means multiply)
hope i make sense

bobsa1

Thankyou so much for help! It means a great deal! If I get A* I shall post back. Once again thanks to Kay74 and vtmil.

DD