I'm currently solving systems of equations which until now has been extremely simplistic. Now this book is changing coefficients on me and I'm completely lost :lol:

I solved the first one just fine

5a + 2b = -16

a + 3b = 15

so:

5(a + 3b) = 5(15)

or 5a + 15b = 75

then:

5a + 2b = -16

subtract

5a + 15b = 75

to get:

-13b = -91

b = 7

then solve for x

a + 3(7) = 15

a = -6

then I substituted x and y into the original problem and it worked...I thought I had the method down.

So I tried it for the second problem:

5d - 3e = 5

d - e = -1

so:

5(d - e) = 5(-1)

or:

5d - 5e = -5

now subtract

5d - 3e = 5

subtract

5d - 5e = -5

to get -2e = 10

e = -5

then:

d - -5 = -1

d = -6

substituting into the original problem does not yield the desirable results...somebody please help!