Solve the following simultaneous equations. 2x + 5y = -4. 7x + y = 19
Simultaneous equations have 2 or more unknowns. This simultaneous equation has 2 unknowns, and 2 equations. This simultaneous equation can be solved using elimination or substitution. Substitution involves substituting a value of one of the unknowns into one equation(for example, x=2) from the equation. Then you can find the other unknown (for example, y). The other way to solve this equation, and for this equation the simpler way, is elimination. This involves eliminating one of the unknowns from the equation. This is done by making the coefficient of the unknown the same in both equations. eq1: 2x + 5y = -4eq2: 7x + y = 19By multiplying eq2 by 5, this makes the coefficients of unknown y the same. eq2(*5): 35x +5y = 95Then we can eliminate the y unknown by subtracting eq1 from eq2(*5).35x + 5y = 95-2x + 5y = -4-----------------(35x - 2x) + (5y - 5y) = (95 - -4)33x = 99 x = 3Once we have found x, we substitute this into one of the original equations (eq1 or eq2). 2(3) + 5y = -46 + 5y = -45y = -4 -6 5y = -10y = -2
Related Maths GCSE answers
All answers ▸Gemma has the same number of sweets as Betty. Gemma gives 24 of her sweets to Betty. Betty now has 5 times as many sweets as Gemma. Workout the total number of sweets that Gemma and Betty have.
Prove that the difference between the squares of any two consecutive integers is equal to the sum of these two integers.
The perimeter of an isosceles triangle is 16cm the lengths of the sides are (x+3)(this is the length of the opposite side as well) and (x+4). Determine the value of x .
Fahima buys 2 packets of bread rolls costing £1.50 for each packet 1 bottle of ketchup costing £1.60 3 packets of sausages Fahima pays with a £10 note. She gets 30p change. Fahima works out that one packet of sausages costs £2.30 Is Fahima right?