Q: How to solve the simultaneous equations 3x+2y=7 and 5x+y=14
When solving simultaneous equations you are aiming to use both equations together to find out the value of x and y for values that with ‘fit’ in each equation.
3x + 2y = 7
5x + y = 14
If we subtract these equations from each other in a way that we end up eliminating y, when can find the value of x. The way we do this is to multiply equation 2 by 2, remembering to multiply both sides of the equation. This gives
2. 10x + 2y = 28
Now, when we subtract equation 1 from equation 2 we get
(10x – 3x) + (2y - 2y) = 28 – 7
7x = 21
x = 3
Now we have found the value of x we can substitute it back into equation 1 to find the value of y.
3x + 2y = 7 and x = 3
9 + 2y = 7
2y = -2
y = -1
KM
Related Maths GCSE answers
All answers ▸Solve algebraically the simultaneous equations, giving your answers in terms of b : 3x+by=5, x-y=-2
Express f(x) = x^2 + 5x + 9 in the form (x + a)^2 + b, stating the values of a and b.
How do you convert between fractions, decimals and percentages?
There are "n" sweets in a bag, six are orange and the rest are yellow. If you take a random sweet from the bag and eat it. Then take at random another one and eat it. The probability of eating two orange sweets is 1/3. Show that n²-n-90=0.