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3x + 5y = 14 (times this entire equation by 3) --> 9x + 15y = 42 4x + 3y = 4 (times this entire equation by 5) --> 20x + 15y = 20Now both of the simultaneous equations have 15y, so you can subtract ...

we first remember the double angle formula, a really important formula. cos(2x) = cos²(x) - sin²(x).We know that sin²(x) + cos²(x) = 1, therefore, cos(2x) = cos...

dy/dx = 3x² - 8x - 3
when dy/dx = 0 , 0 = 3x² - 8x - 3
Factorise : 0= (3x + 1)(x - 3)
when 3x+1 =0 , x = -1/3when x-3=0 , x =3
so x = -1/3 , 3co-ordinates are : (...

Number of sweets = xG=B Gemma and Betty have the same number of sweetsx=x 5(x-24) = x +24 Gemma gives 24 of her sweets to Betty. Betty now has 5 times as many sweets as Gemma.5x - 120 = x + 245x -x = 24 +...

23/5 = 4 and 3/5
5 goes into 23, 4 times with a remainder of 3. Therefore, 23/5 is equivalent to 4 and 3/5.