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Solve x^2 + 15x = - 50

x 2 + 15 x + 50 = 0 (rearrange by adding 50 to both sides) (x + 10)(x + 5) = 0 (factorise the quadratic equation) x + 10 = 0 or x + 5 = 0 (for the above to equal zero, at least one of the bracketed terms mus...
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Answered by Julia S. • Maths tutor
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Explain why it can be said that we live on a 'shrinking' planet?

The term 'shrinking' planet is another way of referring to the process of globalisation, or the deepening and strengthening of ties across transnational borders. This manifests itself in two main ways - good...
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Answered by Paul F. • Geography tutor
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Explain the difference between marginal returns to factor and returns to scale?


The short-run is defined as the period during which one cannot vary at least one of the factors of production, i.e. at least one factor of production is fixed. The long-run is defined as the period during wh...
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Answered by Julia S. • Economics tutor
8374 Views

Explain the concept of price elasticity of demand? How does one calculate it? What is the relationship between price elasticity of demand and firms’ total revenue?

Price elasticity of demand (PED) is a measure of the responsiveness of demand for a product after a change in that product’s price. It is calculated with the following formula: PED = %change in quantity dema...
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Answered by Julia S. • Economics tutor
32540 Views

In one experiment, the temperature of 50 g of water increased from 22.0 °C to 38.4 °C. The mass of alcohol burned was 0.8 g. Calculate the heat energy (Q) in joules, released by burning 0.8 g of the alcohol.

Key Equation: Q = mc ΔT Where: Q = heat transferred (J), m = mass of substance which is heated (g), c = heat capacity of water (J g -1 °C -1 ) and ΔT = temperature change for heated substance (°C) . c = 4.2 ...
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Answered by David B. • Chemistry tutor
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