(-2)= x + 4

Question

have to have pictorial model on balance scale and symbolic model

Answer 1

For a balance scale, you probably want something like this: http://www.eduplace.com/math/mw/background/5/02/graphics/ts_5_2_wi-1.gif

with -2 on one side of the scale, and x+4 on the other. You can also do these balance scales with blocks or shapes on each side instead of numbers, but it may be difficult to show -2 that way.

Answer 2

I think the symbolic model will just be showing the math steps:

   (-2) = x + 4

   -4          -4

   (-6) = x

For the pictoral, you could probably use  a number line with the left side of zero representing negative numbers, the right side positive.

(-8)--(-7)--(-6)--(-5)--(-4)--(-3)--(-2)--(-1)--0--1--2--3--4--5

(-8)--(-7)--(-6)--(-5)--(-4)--(-3)-- (-2)--(-1)-- 0--1--2--3--4--5   this represents (-2)

(-8)--(-7)--(-6)--(-5)--(-4)--(-3)--(-2)--(-1)--0 --1--2--3--4 --5   this represents 4

When you subtract you put the second piece (what is being subtracted) onto the LEFT side of the first piece and see where you end up

(-8)--(-7)--(-6)--(-5)--(-4)--(-3)-- (-2)--(-1)-- 0--1--2--3--4--5

              --(1) --(2)-- (3) --(4)

(-8)--(-7)-- (-6)--(-5)--(-4)--(-3)--(-2)--(-1)-- 0--1--2--3--4--5

This demonstrates, pictorally, that when you take away 4 from (-2) you end up wtih (-6)

Hope this helps