The value of x for which the expressions 7x + 13 and 13x - 7 become equal is _____ .

If  $${{(17)^3-(7)^3}\over (17^2+7^2+k)}=10 $$ , then what is the value of k?

$${2}=x+{1\over{1+{1\over5+{1\over{2}}}}}$$ then the value of x is equal to:

158.25 x 4.6 + 21% of 847+?= 950.935045

What is the value of y in the following equation?
(1÷23) of [2{3 + 4(35 + 7)}] = y

$$\left(4{2\over3} + {5{1\over 6}}\right)× {45 \%} \ of \ 240=?$$

115% of 4880 – 85% of 1640 = ?

$$ 11^{2}-4096^{1\over 4}+100^{1\over2}=?$$