i) Solve the simultaneous equations 4x + 3y + 4 = 0, 3x - 12y + 22 = 0. Could you please teach me step by step, so that I can understand easily and without any problem? Thank you. :)
4x + 3y + 4 = 0, 3x - 12y + 22 = 0.
I think the easiest way to do this is by addition. So we need to make it so two of the variables (one each from each equation) will come to 0 when we add them.
I think the best way to do this is to multiply the first equation by 4 because then we will have 12y to cancel the -12y in the other equation.
So we multiply by 4 and we have
16x + 12y + 16
Now we add that equation to the other. We add the like terms together.
16x + 3x is 19x
12y + (-) 12 y is 0
16 + 22 is 38.
So we have 19x + 38 + 0
Move the 38 to the other side, we have
19x = -38
x = -2
Substitute that back into the first equation to solve for y.
4(-2) + 3y +4 = 0
-8 +3y +4 + 0
3y = 8 - 4
3y = 4
y = 4/3
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