Question

If $3m-5m=-1$ and $2m=n-3$ find the value of $(3m+5n)$ and $(m+2n)$.

• A. -1, 2
• B. -1, -2
• C. 11, 4
• D. -11, -4
• E. 2, 11

Answer 1

The correct option is D

-11, -4

$3m-5n=-\mathrm{1...}\left(i\right)$

$2m=n-\mathrm{3...}\left(ii\right)$

Multiplying (i) by 2 and (ii) by 3 and subtracting (ii) from (i) -

$6m-10n-(6m-3n)=-2+9$

$\Rightarrow$ -7n=7 $\Rightarrow$ n=-1

Substituting value of n (ii), we get

$2m-(-1)=-3\Rightarrow 2m+1=-3$

$\Rightarrow 2m=-4\Rightarrow m=-2$

\((3m+5n) =3(-2)+5(-1) \\

=-6-5=-11 \)

and \((m+2n)=-2+2(-1) \\

=-2-2=-4\)