Solve the simultaneous equations: y = 4x^2 - 9x - 1 and y = 5 - 4x
Subtract the second equation from the first, giving you: 4x^2 -5x -6
Factorise the quadratic: (4x + 3)(x - 2)
x = -0.75
x= 2
Now substitute these values into one of the equations (or both, just to double-check) and get your y value.
y = 5 - 4(-0.75)
y = 8
y = 5 - 4(2)
y = -3
Answer:
x = 2 y = -3
x= -0.75 y= 8
DA
Related Maths GCSE answers
All answers ▸How should I present my working out?
Solve x^2 -7x+10
In an office there are twice as many females as males. 1/4 of the females wear glasses. 3/8 of the males wear glasses. 84 people in the office wear glasses. Work out the number of people in the office.
There are 895 litres of petrol in Mr Turners petrol tank, he uses 19.7 litres of petrol a day. Estimate the number of days it will take him to use all the petrol in the tank.