x = 5, y = 2 is a solution of the linear equation

Solution:

Substituting the values x = 5, y = 2 in

(a) x + 2y = 7, we get

LHS $=5+2(2)=5+4=9 \neq 7=$ RHS

i.e. LHS $\neq$ RHS

(b) 5x + 2y = 7, we get

LHS $=5(5)+2(2)=25+4=29 \neq 7=$ RHS

i.e. LHS $\neq$ RHS

(c) x + y = 7, we get

LHS $=5+2=7=$ RHS

i.e. $\mathrm{LHS}=\mathrm{RHS}$

(d) 5x + y = 7, we get

$\mathrm{LHS}=5(5)+2=25+2=27 \neq 7=\mathrm{RHS}$

i.e. $\mathrm{LHS} \neq \mathrm{RHS}$

Hence, the correct option is (c).