The sum of two numbers is 10, and twice their difference is 4. Find the two numbers by graphing.

Answer 1

Hello, Marat,

We can form two equations from the sentences. I'll use X and Y for the two numbers:

The sum of two numbers is 10

X + Y = 10

twice their difference is 4

2(X-Y) = 4

I'll rewrite both equations in slope-intercept form:

Y = -X + 10, and

2X - 2Y = 4

-2Y = -2X + 4

Y = X - 2

Graph these two lines. Where they intersect will give us the values of X and Y.

My graph won't fit here. You should see two perpendicular lines intersecting at (6,4)

Bob

Answer 2

x+y= 10

x-y = 4

2x =14

x =7

y =3