Solve the linear simultaneous equations: 3x + 5y = 45, 2x - 9y = -7
x = 10, y = 3. From the second equation, we have x = (9y - 7)/2. Substituting this expression for x into the first equation gives 3(9y - 7)/2 + 5y = 45. 3(9y - 7) + 10y = 90. 27y - 21 + 10y = 90. 37y = 111. y = 111/37 = 3. Finally, substituting our result for y into our expression for x gives x = (27 - 7)/2 = 20/2 = 10
CW
Related Maths GCSE answers
All answers ▸A scalene triangle has side lengths a=xcm, b=10cm and c=15cm. The angle A=105 degrees is opposite side a. Using the cosine rule, find the value of x to 3 s.f.
A circular table has a diameter 140 cm. Calculate the area of the table in cm^2, leaving your answer as a multiple of pi.
In a right-angled triangle calculate the length of the hypotenuse when the side lengths at 5cm and 7cm. Leave your answer as a surd.
Plot out y= x^2 - x - 2 for values of x from -3 to +3 and label the turning point