Hello, I was wondering if someone could help explain a couple of techniques envolved in solving simultaneous equations because I think I'm getting confused on which method to use and if I'm doing that method correctly.
On this question for example
7a + 8b = 17 (1)
4a + 6b = 9 (2)
I mutilply the coeffecient of b in equation (2) to the top equation and get
42a + 48b = 102
then multiply the coeffecient of b in equation (1) to the bottom equation
32a + 48b = 72
____________________________
the b gets cancelled out so then I subtract right? 42a - 32a = 10a
102 - 72 = 30
so does that mean 10a gets subtracted from 30 to leave a = 20?
Is this the correct method for this type of question? If not could someone perhaps go over where I've gone wrong. Thanks for your help.
On this question for example
7a + 8b = 17 (1)
4a + 6b = 9 (2)
I mutilply the coeffecient of b in equation (2) to the top equation and get
42a + 48b = 102
then multiply the coeffecient of b in equation (1) to the bottom equation
32a + 48b = 72
____________________________
the b gets cancelled out so then I subtract right? 42a - 32a = 10a
102 - 72 = 30
so does that mean 10a gets subtracted from 30 to leave a = 20?
Is this the correct method for this type of question? If not could someone perhaps go over where I've gone wrong. Thanks for your help.