Question

Explain why the expression below always has the same value, no matter what number other than zero you choose for p.

P-2P+3p-4P

---------------

P

Answer 1

Answer and explanation:

The expression P-2P+3P-4P cannot have the same values for different values of P. Let us illustrate this by substituting different values of P in the expression:

If P= 2

Substitute P=2 in the expression

2-2×2+3×2-4×2

=2-4+6-8

=-4

If P= 3

Substitute P=3 in the expression

3-2×3+3×3-4×3

=3-6+9-12

=-6

If P = 1

Substitute P=1 in the expression

1-2×1+3×1-4×1

= 1-2+3-4

= -2

If P = -2

Substitute P=1 in the expression

-2-2×-2+3×-2-4×-2

= -2+4-6+8

=4

Therefore we can see from the above that the expression has different values for different values of P