How do i make y the subject in these equations? -by transposeing each of the equations to make the pronumerals.3x-4y+12=0 (y) 5p=2-3k (k) a=3b-0.5c

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neela's profile pic

neela | High School Teacher | (Level 3) Valedictorian

Posted on

To make y  the subject of 3x-4y+12=0, Add 4y to both sides, then,

3x-4y+12+4y = 4y .


3x+12 = 4y

Divide by 4 both sides:

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


ii) To make k the subject in 5p=2-3k, add 3k to both sides, and then sibtract 5p from both sides which makes k's to the left and p's and numbers to right. Then divide both sides by the coefficient of k both sides  left:

5p +3k = 2-3k+3k.

5p +3k = 2

5p+3k-5p = 2-5p or

3k = 2-5p

3k/3 = (2-5p)/3 or

k= (2-5p)/3.

iii) Making  b subject in a=3b-0.5c: Add 0.5c to both sidesas below:

a+0.5c = 3b-0.5c+0.5c or

a+0.5c = 3b. Divide both sides by 3:

(a+0.5c)/3 =3b/3 Or

(a+0.5c)/3 = b Or


ashraf-ghanem's profile pic

ashraf-ghanem | Teacher | eNotes Newbie

Posted on

to make y the subject try to put it alone on one side with (+ve ) sign , so move  4y to the other side


then try to get rid of the number multiplied by y which is 4

the opposite operation of multiplying is dividing

so we divides by 4


3/4 x + 3 = y                or     y = 3/4 x + 3

the 2nd. equation

5p=2-3k   ( send 2k to the left side and 5p to the right side )

3k = 2 - 5p             ( divide by 3)

3k/3 = 2/3 -5/3p

k = 2/3 - 5/3 p

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