Question

If C = 2a^2 - 5 and D = 3 - a,then C -2D equals

Answer 1

Answer:

$\large\boxed{C-2D==2a^2+2a-11}$

Step-by-step explanation:

$C=2a^2-5,\ D=3-a\\\\C-2D=?\\\\\text{Substitute:}\\\\(2a^2-5)-2(3-a)\qquad\text{use distributive property}\\\\=2a^2-5+(-2)(3)+(-2)(-a)=2a^2-5-6+2a=2a^2+2a-11$

Answer 2

Answer:

$2a^2+2a-11$

Step-by-step explanation:

Given,

$C = 2a^2 - 5------(1)$

$D=3 - a-------(2)$

Thus,  

$C-2D = 2a^2 - 5-2(3 - a)$  ( From equation (1) and (2) )

$=2a^2 - 5 - 6 + 2a$            ( By distribution property )

$=2a^2+2a-11$                      ( Operating like terms )

Hence, C - 2D is equal to $2a^2+2a-11$