the sum of two numbers is 16 the difference is 4

Answer 1

This is a "System of Equations" problem. You start by rewriting it in the form of two equations using algebra.

X+Y = 16

X-Y =4

Put one equation so it is equal to one variable, in this case

X-Y = 4

Add Y to both sides:

X = 4+Y

The plug that equation int the other

X + Y =16

We know that X equals 4+Y:

(4+Y)+Y = 16

2Y+4 = 16

2Y = 12

Y=6

Then plug that into either equation to solve for X:

X + Y = 16

X + 6 = 16

X= 10