Question: Real Numbers
Identifying equivalent algebraic expressions
(a) Select all equivalent expressions from the list for the expression.
5x + 25
5(x + 5) 5\cdot x + 5\cdot 5 5(5x + 1) 30x
(b) Select all equivalent expressions from the list for the expression.
10 + 13y - 7 - y
3y + 12y 12 + 3y 3y + 12 12y + 3
1. **Problem statement:**
(a) Find expressions equivalent to $$5x + 25$$ from the list: $$5(x + 5), 5\cdot x + 5\cdot 5, 5(5x + 1), 30x$$.
(b) Find expressions equivalent to $$10 + 13y - 7 - y$$ from the list: $$3y + 12y, 12 + 3y, 3y + 12, 12y + 3$$.
2. **Recall the distributive property and combining like terms:**
- Distributive property: $$a(b + c) = ab + ac$$.
- Combine like terms by adding or subtracting coefficients of the same variable.
3. **Part (a) simplification and checking equivalence:**
- Original expression: $$5x + 25$$.
- Check $$5(x + 5)$$:
$$5(x + 5) = 5 \cdot x + 5 \cdot 5 = 5x + 25$$, which matches the original.
- Check $$5 \cdot x + 5 \cdot 5$$:
This is exactly $$5x + 25$$, so equivalent.
- Check $$5(5x + 1)$$:
$$5(5x + 1) = 25x + 5$$, which is not equal to $$5x + 25$$.
- Check $$30x$$:
This is just $$30x$$, which is not equal to $$5x + 25$$.
4. **Part (b) simplification and checking equivalence:**
- Original expression: $$10 + 13y - 7 - y$$.
- Combine like terms:
$$10 - 7 = 3$$
$$13y - y = 12y$$
So, simplified expression is $$3 + 12y$$.
- Check $$3y + 12y$$:
$$3y + 12y = 15y$$, not equal to $$3 + 12y$$.
- Check $$12 + 3y$$:
This is $$12 + 3y$$, not equal to $$3 + 12y$$.
- Check $$3y + 12$$:
This is $$3y + 12$$, which is the same as $$12 + 3y$$, not equal to $$3 + 12y$$.
- Check $$12y + 3$$:
This is $$12y + 3$$, which matches $$3 + 12y$$ (order does not matter in addition), so equivalent.
5. **Final answers:**
- (a) Equivalent expressions: $$5(x + 5), 5 \cdot x + 5 \cdot 5$$.
- (b) Equivalent expression: $$12y + 3$$.