Answer:
A = 21
J = 2A = 42
C= A+5 =26
Step-by-step explanation:
C= christines text messages
J = jims messages
A = ali messages
Jim sent  2 times as many messages as Ali.
J = 2A
Ali sent  5 fewer messages than Christine.
A =C-5
A+5 =C
Christine, Jim, and Ali sent a total of 89 text messages
C+J+A = 89
substitute
C +5= A
A+5 +J+A = 89
combine like terms
2A +5+J = 89
now substitute J = 2A
2A +5+2A = 89
combine like terms
4A +5 = 89
subtract 5 to each side
4A +5-5 = 89-5
4A = 84
divide by 4
A = 21
J = 2A = 42
C= A+5 =26
