Expression substitution

Substitute for variables and specify the value of the expression:
a) x + y + 2x-3y. x = 1, y = 2
b) a + 5b-a + 4b. a = 8, b = -8
c) mn-5mn + 6mn. M = -3, n = -4
d) k + 10m + 5k-6m + 13km. k = 1, m = 0

Final Answer:

A =  -1
B =  -72
C =  24
D =  6

Step-by-step explanation:

$$\begin{gathered} x=1 \\ y=2 \\ A=x+y+2x-3y=1+2+2\cdot 1-3\cdot 2=-1 \end{gathered}$$

$$\begin{gathered} a=8 \\ b=-8 \\ B=a+5b-a+4b=8+5\cdot (-8)-8+4\cdot (-8)=-72 \end{gathered}$$

$$\begin{gathered} m=-3 \\ n=-4 \\ C=m\cdot n-5m\cdot n+6m\cdot n=(-3)\cdot (-4)-5\cdot (-3)\cdot (-4)+6\cdot (-3)\cdot (-4)=24 \end{gathered}$$

$$\begin{gathered} k=1 \\ m=0 \\ D=k+10m+5k-6m+13k\cdot m=1+10\cdot 0+5\cdot 1-6\cdot 0+13\cdot 1\cdot 0=6 \end{gathered}$$

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