Let’s solve each problem step by step.
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Problem 1: 6x = 18, for x
We want to get x alone on one side.
Since x is multiplied by 6, we divide both sides by 6:
6x ÷ 6 = 18 ÷ 6
→ x = 3
✔ Check: 6 × 3 = 18 → Correct!
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Problem 2: A = (1/2)h(a + b), for a
We need to isolate “a”.
Step 1: Multiply both sides by 2 to eliminate the fraction:
2A = h(a + b)
Step 2: Divide both sides by h:
(2A)/h = a + b
Step 3: Subtract b from both sides:
(2A)/h - b = a
So, a = (2A)/h - b
✔ Check: Plug back in — if a = (2A)/h - b, then a + b = (2A)/h → multiply by h → h(a+b) = 2A → half of that is A → matches original equation. Good!
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Problem 3: y = (f + g)/3, for g
Multiply both sides by 3:
3y = f + g
Subtract f from both sides:
3y - f = g
So, g = 3y - f
✔ Check: If g = 3y - f, then f + g = f + 3y - f = 3y → divided by 3 is y → correct.
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Problem 4: 3ax + b = c, for x
Subtract b from both sides:
3ax = c - b
Divide both sides by 3a:
x = (c - b)/(3a)
✔ Check: Plug back in — 3a × [(c-b)/(3a)] + b = (c-b) + b = c → correct.
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Problem 5: v = (1/3)Bh, for h
Multiply both sides by 3:
3v = Bh
Divide both sides by B:
h = (3v)/B
✔ Check: (1/3)B × (3v/B) = (1/3)(3v) = v → correct.
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Problem 6: y - y₁ = m(x - x₁), for x
Add y₁ to both sides:
y = m(x - x₁) + y₁ → but better to keep as:
y - y₁ = m(x - x₁)
Divide both sides by m:
(y - y₁)/m = x - x₁
Add x₁ to both sides:
x = (y - y₁)/m + x₁
✔ Check: Plug into right side: m[ ((y-y₁)/m + x₁) - x₁ ] = m[(y-y₁)/m] = y - y₁ → matches left side. Good.
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Problem 7: s = 2(lw + lh + wh), for w
First, divide both sides by 2:
s/2 = lw + lh + wh
Group terms with w:
s/2 = w(l + h) + lh
Subtract lh from both sides:
s/2 - lh = w(l + h)
Now divide both sides by (l + h):
w = (s/2 - lh) / (l + h)
You can also write it as:
w = [s - 2lh] / [2(l + h)] ← multiplying numerator and denominator by 2 to eliminate fraction inside.
Either form is acceptable, but let’s use the cleaner version:
w = (s - 2lh) / [2(l + h)]
✔ Check: Let’s plug numbers. Suppose l=2, h=3, w=4 → then s = 2(2×4 + 2×3 + 3×4) = 2(8+6+12)=2(26)=52
Now compute w using formula: (52 - 2×2×3) / [2(2+3)] = (52-12)/10 = 40/10 = 4 → correct.
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Problem 8: g = 4ca - 3ba, for a
Factor out ‘a’ on the right:
g = a(4c - 3b)
Now divide both sides by (4c - 3b):
a = g / (4c - 3b)
✔ Check: Plug back — a(4c - 3b) = [g/(4c-3b)] × (4c-3b) = g → correct.
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Final Answers:
1. x = 3
2. a = (2A)/h - b
3. g = 3y - f
4. x = (c - b)/(3a)
5. h = 3v/B
6. x = (y - y₁)/m + x₁
7. w = (s - 2lh) / [2(l + h)]
8. a = g / (4c - 3b)
Parent Tip: Review the logic above to help your child master the concept of literal equations worksheet answers.