Substitution Into Algebraic Expressions - Free Printable

Let's solve each part step by step using the order of operations (PEMDAS: Parentheses, Exponents, Multiplication and Division from left to right, Addition and Subtraction from left to right) and substitute the given values into the expressions.

---

a) $ 3n + 4 $, where $ n = 2 $

Substitute $ n = 2 $:

$$
3(2) + 4 = 6 + 4 = 10
$$

✔ Answer: 10

---

b) $ 7 - 2m $, where $ m = 3 $

Substitute $ m = 3 $:

$$
7 - 2(3) = 7 - 6 = 1
$$

✔ Answer: 1

---

c) $ ab + 5 $, where $ a = 3 $, $ b = 4 $

Substitute $ a = 3 $, $ b = 4 $:

$$
(3)(4) + 5 = 12 + 5 = 17
$$

✔ Answer: 17

---

d) $ \frac{7 + y}{2} $, where $ y = 5 $

Substitute $ y = 5 $:

$$
\frac{7 + 5}{2} = \frac{12}{2} = 6
$$

✔ Answer: 6

---

e) $ \frac{4u - 5}{u} $, where $ u = 10 $

Substitute $ u = 10 $:

$$
\frac{4(10) - 5}{10} = \frac{40 - 5}{10} = \frac{35}{10} = 3.5
$$

Or as a fraction: $ \frac{7}{2} $

✔ Answer: 3.5 or $ \frac{7}{2} $

---

✔ Final Answers:

a) 10
b) 1
c) 17
d) 6
e) 3.5 (or $ \frac{7}{2} $)

Let me know if you'd like these explained in more detail!