Add 5 to 5, or multiple 5 by 2.
The product of a scalar and a matrix is found by multiplying each element of the matrix by the scalar. Multiply each element by -4.
... [4 -12 -24 12]
Since we know that a - 2 will equal 8, it is safe to assume that 8 + 2 = 10. Therefore a=10.
The answer is 19.. substitute -1 into the function whenever you see x put -1 there. This implies that 3+16 =19