Explanation:
x+5Y=13...... 1
4x +7y=0..... 2
from eqn 1
x =13-5y
substitute into eqn 2
52-20y +7y=0
52-13y=0
52=13y
y=52÷13
y=4
substitute Y into eqn 2
x +5y=13
x + 5(4)= 13
x+ 20=13
x=13-20
x=-7
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