X = 6 after distributing then adding 39 to both sides and then divide by 13
A = b+5
ab = 3300
(b+5)b = 3300
b² +5b -3300 = 0 (quadratic formula)
b=55
a=60 (by first relation)
Multiply 2x-2y=10 by 2,
4x-4y=20,
given:4x-5y=17
y=3
pluck it in
2x-6=10
move the 6 to the right
2x=16
divide
x=8
y=3
Answer:
Yes О.31243576 is a rational number