David used 40 feet of braid to trim the edges of a quilt that is 12 feet long. how wide is the quilt? use the formula p=2l+2w.
a)3 1/3 feet
b)8 feet
c)14 feet
d) 28 ft
show your work of how u got the answer.

P = 2W +2L  step is keep 2L in one side of equation , and move every thing else to the other side.

 
In moving any quantity from one side to other, change the sign. ( equivalent of adding or subtracting equal                                                                                                  quantity from both sides of equation).

2L = P - 2W   divide both sides by 2:
 L = p/2 - w    Step is the same as solving  X in equation of  8 = 2X + 16  2X = 8 -16 = 8    X =4 . But, here you solve one variable in terms of other variables.

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.