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Solve the following equations:1. 15(x – 1) + 4(x + 3) = 2 (7 + x) 2. 3 (5z – 7) +2 (9z – 11) = 4 (8z – 7) – 111 3. 8(x – 3) – (6 – 2x) = 2(x + 2) – 5 (5 – x) 4. 3(n – 4)+2(4n – 5) = 5(n + 2) + 16 |
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Answer» 1. 15(x – 1) + 4(x + 3) = 2(7 + x) ⇒ 15x – 15 + 4x + 12= 14 + 2x ⇒ 19x – 3 = 14 + 2x ⇒ 19x – 2x = 14 + 3 ⇒ 17x = 17 x = \(\frac{17}{17}\) = 1 ∴ x = 1 2. 3(5z – 7) + 2(9z – 11) = 4(8z – 7) – 111 ⇒ 15z – 21 + 18z – 22 = 32z – 28 – 111 ⇒ 33z – 43 = 32z – 139 ⇒ 33z – 32z = – 139 + 43 ∴ z = – 96 3. 8(x – 3) – (6 – 2x) = 2(x + 2) - 5(5 – x) ⇒ 8x – 24 – 6 + 2x = 2x + 4 – 25 + 5x ⇒ 8x – 30 = 5x – 21 ⇒ 8x – 5x= –21 + 30 ⇒ 3x = 9 ∴ x = 3 4. 3(n – 4) + 2(4n – 5) = 5(n + 2) + 16 ⇒ 3n – 12 + 8n – 10 = 5n + 10 + 16 ⇒ 11n – 22 = 5n + 26 ⇒ 11n – 5n = 26 + 22 ⇒ 6n =48 ⇒ n = \(\frac{48}6\) = 8 ∴ n = 8 |
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