If $\begin{bmatrix}2a+b&a-2b\\5c-d&4c+3d\end{bmatrix}=\begin{bmatrix}4&-3\\11&24\end{bmatrix}$, then the value of $a + 2b - 3c + 4d$ is equal to |
4 12 24 30 |
12 |
The correct answer is Option (2) → 12 Given $2a+b=4$ $a-2b=-3$ $5c-d=11$ $4c+3d=24$ From $a-2b=-3$ $a=-3+2b$ Substitute in $2a+b=4$ $2(-3+2b)+b=4$ $-6+4b+b=4$ $5b=10$ $b=2$ $a=-3+2(2)=1$ From $5c-d=11$ $d=5c-11$ Substitute in $4c+3d=24$ $4c+3(5c-11)=24$ $4c+15c-33=24$ $19c=57$ $c=3$ $d=5(3)-11=4$ Now $a+2b-3c+4d=1+2(2)-3(3)+4(4)$ $=1+4-9+16$ $=12$ The value of $a+2b-3c+4d$ is $12$. |