Example

Solving 5(a3)+5=105(a - 3) + 5 = -10 by Distributing and Combining Like Terms

To solve the equation 5(a3)+5=105(a - 3) + 5 = -10, begin by simplifying the left side before isolating the variable.

Step 1 — Distribute: Multiply 55 by each term inside the parentheses: 5a=5a5 \cdot a = 5a and 5(3)=155 \cdot (-3) = -15. The equation becomes:

5a15+5=105a - 15 + 5 = -10

Step 2 — Combine like terms: On the left side, the constants 15-15 and 55 are like terms: 15+5=10-15 + 5 = -10. The equation simplifies to:

5a10=105a - 10 = -10

Step 3 — Add 1010 to both sides: Use the Addition Property of Equality to move the constant 10-10 to the right side:

5a10+10=10+105a - 10 + 10 = -10 + 10

5a=05a = 0

Step 4 — Divide both sides by 55: Apply the Division Property of Equality to make the coefficient equal to 11:

5a5=05\frac{5a}{5} = \frac{0}{5}

a=0a = 0

Step 5 — Check by substitution: Replace aa with 00 in the original equation:

5(03)+5=?105(0 - 3) + 5 \stackrel{?}{=} -10

5(3)+5=?105(-3) + 5 \stackrel{?}{=} -10

15+5=?10-15 + 5 \stackrel{?}{=} -10

10=10-10 = -10 \checkmark

Because both sides are equal, a=0a = 0 is confirmed as the correct solution. This example reinforces that 00 is a perfectly valid solution to an equation — when the constant terms on the right side cancel completely after isolating the variable term, dividing any coefficient into 00 always yields 00.

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Updated 2026-04-21

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