X : y = 5 : 3
and
x + y = 56
Work out the value of x - y

14

Step-by-step explanation:

x / y = 5 / 3, then 3x = 5y , x = 5/3y

we can type 5/3y instead of x ;

5/3y + y = 8/3y = 56, then y = 21

.

now let's find x ;

x - 21 = 56, then x = 35

x - y = 35 - 21 = 14

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x

multiplication is multiplication.   it might feel harder depending on what level of math you are in, but generally it will be the same old stuff, while implementing some new concepts and methods of solving work.