how would i solve this system?
with either elimination or substitution.
2r + 3t = -10
-1r - 2t = 12
2007-11-01 13:12:22 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
By substitution, notice that the second equation is the same as r = -12 - 2t
Substitute that into the first equation
2(-12 - 2t) + 3t = -10
-24 -4t + 3t = -10
-14 = t
Now put that back into the second equation
-r - 2*(-14) = 12
-r + 28 = 12
16 = r
Check the answer
2*16 +3(-14) = -10
32 - 42 = -10
Again
-1(16) -2(-14) = 12
-16 + 28 = 12
Checked and doublechecked.
2007-11-01 14:07:44 · answer #1 · answered by Steve A 7 · 0⤊ 0⤋
multiply 2nd eqn. by 2
now you have 2r + 3t = -10
-2r - 4t = 24
add and get -1t = 14 so t = -14
substitute 2r + 3(-14) = -10
solve for r 2r = -52 r = -26
answer (-26 , -14)
2007-11-01 20:17:54 · answer #2 · answered by ssssh 5 · 0⤊ 1⤋