I don't understand why you add the equations together? Would you mind doing a written method?
You add them because then the y's cancel, thus leaving you only with an x which you can solve for. Once you have your x, substitute that into one of the two equations and solve for y.
When solving simultaneous equations you always aim to get rid off either x or y and in this case we choose y because it's easier by having the same coefficient (the number next to it).
I don't understand why you add the equations together? Would you mind doing a written method?
You have a pair of simultaneous equations with two variables, x and y. The "x"s and "y"s are of the same value in both equations. But in order to obtain any of their values, you need to make an equation with only one variable, x or y, and then solve for that variable. Then substitute that value into one of the original equations.
(3x - 2y = 7) [7x]
We have xs and ys. (3x - 2y) is equal to (7), and [7x + 2y] is equal to [13], so: (3x - 2y) + [7x + 2y] = (7) + [13]
Here everything is being added or subtracted, so we can simply remove the brackets and simplify:
3x + 7x + 2y - 2y = 7 + 13 10x = 20 <---- Indeed, I made a numerical error in my rushed response earlier, my apologies for that.
From that, you can solve the value of x, and substitute that numerical value in the place of x into any of the two original equations, to leave just one variable (y in this case).
I have tried to do this one but dont know what to do next:
6x + 2y = 22 (1) 5x + 4y = 23 (2)
First I made the coefficients the same:
6x + 2y = 22 (x 4) 5x + 4y = 23 (x 2)
12x + 8y = 88 10x + 8y = 46
Well done, now take one away from the other because if you were to add them, you would end up with 22x+16y=134 which you can't solve on its own. It's really as simple as that. I hope you understand that by combining these two equations through means of subtraction/addition, you can solve for one of the variables which wouldn't be possible given only one of those equations.
Well done, now take one away from the other because if you were to add them, you would end up with 22x+16y=134 which you can't solve on its own. It's really as simple as that. I hope you understand that by combining these two equations through means of subtraction/addition, you can solve for one of the variables which wouldn't be possible given only one of those equations.
12x + 8y = 88 10x + 8y = 46
So would it now be 10x = 42
then i would divide by 10 to get x on its own then do the same to 42 and I get x = 4.2