Question

who knows what is the answer?

Answer 1

set x=10 as equation 1 and 3x+5y=20 as equation 2

x=10----------(1)
3x+5y=20-----------(2)

substitute (1) into (2),
3(10)+5y=20
30+5y=20
30–20=–5y
10=–5y
5y=–10
y=–10÷5
y=–2

final ans:(10,–2)