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Find the stationary point of 3x^2+7x

dy/dx=6x+7 6x+7=0 x=-7/6 Sub back into original equation; y=98/6
HS
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Solve the simultaneous equations; 3x+2y=11 and 2x-2y=14

2y=11-3x and 2y=2x-14 11-3x=2x-14 25=5x thus x=5 3(5) +2y=11 2y=-4 thus y=-2
HS
Answered by Harrie S. • Maths tutor
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A student wishes to investigate the effect of surface area on the rate of reaction between marble chips and hydrochloric acid. Which variables should he control?

Concentration of HCl, Mass of marble chips (use excess HCl).
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Answered by Alfie B. • Chemistry tutor
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Expand the following expression: -5x(x-7)(x+3)

Expansion of the given expression will result in x to the 3rd power, as there are 3 parts involving x, multiplied together. Let's ignore -5x for a second, and multiply the two expressions in brackets (using ...
MS
Answered by Matas S. • Maths tutor
5609 Views

Describe the changes in forces experienced by a parachutist after they have started falling

Initially, the parachutist will experience a greater downwards force due to gravity which causes them to accelatae downwards. As they accelarate, the upwards force of air resistance will increase. They will ...
IN
Answered by Iona N. • Physics tutor
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