Answer:
see explanation
Step-by-step explanation:
(a)
Given y is directly proportional to x then the equation relating them is
y = kx ← k is the constant of proportion
To find k use the condition when x = 3, y = 18 , then
18 = 3k ( divide both sides by 3 )
6 = k
y = 6x ← equation of proportion
(b)
(i)
when x = 12 , then
y = 6 × 12 = 72
(ii)
when y = 42
42 = 6x ( divide both sides by 6 )
7 = x
Answer: 2x^2-7x-15
Step-by-step explanation:
reorder the terms (x*2+3)*(x-5)
multiply the parentheses
(2x+3)*(x-5)
collect like terms (2x^2-10x+3x-15)
product= 2x^2-7x-15
Answer:
48x⁷ - 64x + 9
Step-by-step explanation:
Step 1: Write out expression
4x(12x⁶ - 4²) + 9
Step 2: Evaluate exponent
4x(12x⁶ - 16) + 9
Step 3: Distribute
48x⁷ - 64x + 9