1. Simplify the following expressions and express answers with positive indices.
(a) (−3a²b)³ × (ab⁻²) × (2b³)²
(b) (x²y⁻¹z)³ ÷ (x⁻¹y²z⁻²)
2. (a) Expand (m − 7)(m + 7).
(b) Hence, or otherwise, expand (p + q − 7)(p + q + 7).
3. Let C and D be constants. Find the values of C and D if (4x + C)(x − 3) = 4x² + Dx − 3C.
4. (a) Simplify (5y² − 3y + 4) − (2y² + 7y − 1).
(b) Hence, find the value of the expression in (a) when y = −2.
5. Expand and simplify:
(a) −3(u v − 2)
(b) t²(3t − s) + (t² + 9)(3t + s)
6. (a) Factorize: pq + 7q − 5p − 35.
(b) Hence, factorize: (q − 5)² + pq + 7q − 5p − 35.
7. (a) Convert 1010110₂ to a denary number. Show your steps.
(b) Convert 73₁₀ to a binary number. Show your steps.
8. (a) Make w the subject of the formula z = (200 − 5w)/(t − 3w).
(b) If z = 1/5 and t = 250, find the value of w.
9. Simplify the following:
(a) (3x − 12y)/(9x − 36y)
(b) (2p + 6)/(p² − 9) ÷ (p + 3)/(2p − 6)
(c) 1/(y − 4) + 1/(y + 4) − 2y/((y − 4)(y + 4))
10. It is given that the mass of a sodium atom is approximately 3.8 × 10⁻²³ g and the mass of a chlorine atom is approximately 5.9 × 10⁻²³ g. A molecule of sodium chloride (NaCl) consists of one sodium atom and one chlorine atom.
(a) Express the mass of one NaCl molecule in scientific notation.
(b) How many NaCl molecules are there in 2.0 kg of NaCl? Express your answer in scientific notation, correct to 3 significant figures.