00:02
For this problem, if i want to use the elimination method, all i need to do is multiply one of the equations by negative 1 so that the d terms will be opposites.
00:12
So i'll go ahead and multiply the first equation by negative 1.
00:15
And that gives me negative 5c minus 2d equals 5, and i'll leave the second equation alone, 6c plus 2d equals negative 10.
00:25
Now if i add those equations together, the c terms add up to c, the d terms are eliminated, and the constants add to negative 5.
00:34
So now we know c is negative 5.
00:37
Now i'm going to go back and label my equations 1 and 2, and choose either equation 1 or 2, doesn't matter which, to find the value of d.
00:45
I'm going to use equation 1.
00:47
So we have 5 times c, which would be 5 times negative 5, plus 2 times d equals negative 5...