Question

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Explanation:

Step1: Simplify the first expression

$11x - 3x + 8x = (11-3+8)x = 16x$

Step2: Check options for (a)

$8x+8x=(8+8)x=16x$; others do not equal 16x.

Step3: Simplify the second expression

$5(1+4y)=5\cdot1 + 5\cdot4y=5+20y$

Step4: Check options for (b)

$5+20y$ matches the simplified form, and $5\cdot1 + 5\cdot4y$ is the expanded form before combining terms.

Answer:

(a) 16x, 8x+8x
(b) 5+20y, $5\cdot1 + 5\cdot4y$