Let $M=4a^2 - 2b^2 +a$. Let $j$ be the value of $M$ when $a=5$ and $b=3$, and let $k$ be the value of $M$ when $a=-1$ and $b=4$. Calculate $j+2k$.
j = 4(5)^2 - 2(3)^2 +5 = 100 - 18 + 5 = 87
k = 4(-1)^2 - 2(4)^2 + 5 = 4 - 32 + 5 = -23
j + 2k =
87 + 2(-23) =
87 - 46 =
41
i think its wrong
Can you find the error? Hint: It's the value of k