Solve for the first variable in one the equations then substitute the result into the other equation so the answer is (2,5)
let's firstly, convert the mixed fractions to improper, and then do equation.
![\bf \stackrel{mixed}{3\frac{4}{5}}\implies \cfrac{3\cdot 5+4}{5}\implies \stackrel{improper}{\cfrac{19}{5}} ~\hfill \stackrel{mixed}{2\frac{5}{7}}\implies \cfrac{2\cdot 7+5}{7}\implies \stackrel{improper}{\cfrac{19}{7}} \\\\[-0.35em] \rule{34em}{0.25pt}](https://tex.z-dn.net/?f=%5Cbf%20%5Cstackrel%7Bmixed%7D%7B3%5Cfrac%7B4%7D%7B5%7D%7D%5Cimplies%20%5Ccfrac%7B3%5Ccdot%205%2B4%7D%7B5%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B19%7D%7B5%7D%7D%0A~%5Chfill%0A%5Cstackrel%7Bmixed%7D%7B2%5Cfrac%7B5%7D%7B7%7D%7D%5Cimplies%20%5Ccfrac%7B2%5Ccdot%207%2B5%7D%7B7%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B19%7D%7B7%7D%7D%0A%5C%5C%5C%5C%5B-0.35em%5D%0A%5Crule%7B34em%7D%7B0.25pt%7D)

Y + 4x = 8
y = 8 - 4x
substitute 8 - 4x for y in the other equation.
5x + 2(8 - 4x) = 13
5x + 16 - 8x = 13
-3x = -3
x = 1
y = 8 - 4(1) = 4
The answer to this is A. 650. You find the surface area of the two cubes, then the rectangular prism, then you add them together.<span />