Solve the simultaneous equations 2x + 7y = 15 and 3x + 6y = 21
Find the lowest common multiple of 2 and 3, which is 6. Multiply each term in the first equation by 3, and each term in the second equation by 2 to produce two equations with the same coefficient of x (which is 6). The two resulting equations are 6x + 21y = 45 and 6x + 12y = 42. Now you need to cancel the x term by subtracting the second equation from the first which leaves you with 9y = 3, y =1/3. Now sub y=1/3 into any of the four equations to find an x value of 19/3.
Copy of method worked through ready to show in session
IR
Related Maths GCSE answers
All answers ▸Solve the following, (3/4 + 2/5)^2
What is 16^(3/2)
Find the values of X and Y from the simultaneous equations: 1) 2x + 5y = 33 2) x + 3y = 19
A ball, dropped vertically, falls d metres in t seconds. d is directly proportional to the square of t. The ball drops 45 metres in the first 3 seconds. How many metres does the ball drop in the next 7 seconds?