orderd pairs?

Question

I do not understand how to substitute a fraction for a letter.
ex.

3x+4y=12 (5/3,y ) how would I work out this solution and put 5/3 in the place of x?

Answer 1

(3)(5/3) + 4y = 12
or 5 + 4y = 12
then 4y = 7, or y = 7/4

Answer 2

Just put (5/3) instead of x (think of x as though any number could take its place. All letters are supposed to be thought of that way. In the situation you have, 5/3 must take its place. These letters are called variables since they can vary to any number they wish!)
3 (5/3) + 4y = 12
5 + 4y = 12 Multiplied 3 * (5/3)
4y = 7 Subtracted 5 from both sides
y = 7/4 Divided both sides by 4
Thus, the ordered pair is (5/3, 7/4).

Answer 3

first rearrange the equation for y:

4y = 12 - 3x hence y = 3-(3/4)x

now substitute for x=5/3

hence
y = 3 - (3/4)(5/3) = 3 -5/4 = 7/4

Answer 4

an ordered pair is (x,y) so you can substitute the x (5/3) into the equation.

3(5/3) + 4y =12
5+4y=12
4y=7
y=7/4

(5/3, 7/4)

Answer 5

Like this:

3x = 3 times x

substitute 5/3 for x

so you have 3 times 5/3

the 3's cancel out, right? (do you see that you have 3*5/3?)

so, 3 times 5/3 = 5

Put that back into your equation and you have:

5 + 4y = 12

Now subtract 5 from each side to get:

4y = 7

Now divide both sides by 4 to get:

y = 7/4

Answer 6

3(3/5)+4y=12 or find decimal equivilant of fraction, 3(1.6repeating)+4y=12

Answer 7

3x + 4y = 12
4y = -3x + 12
y = (-3/4)x + 3

y = (-3/4)(5/3) + 3
y = (-15/12) + 3
y = (-5/4) + 3
y = (-5/4) + (12/4)
y = (-5 + 12)/4
y = (7/4)

Answer 8

3 x (5/3) +4Y =12

5+4Y=12
4Y=7
Y= 7/4

so, one solution is the ordered pair, (5/3, 7/4)

Answer 9

These sites should help...
http://www.terragon.com/tkobrien/algebra/topics/orderdpairs/op.html
http://www.teacherschoice.com.au/Maths_Library/Coordinates/plotting_ordered_pairs.htm
http://mathforum.org/library/drmath/view/52903.html
http://www.math.com/
http://www.algebra.com/
http://www.purplemath.com/modules/index.htm