2) …x * y =11

from 1)….x =7 – y ….replace to #2

……………(7-y ) *y=11

……………7y – y ^ 2 = 11

…………..7y -y^2 -11 = 0

now what is the # b4 y….7 right call this b ok

………what is the #b4 y^2.. -1 right call this a

and call the free # which is 11 c ok

so a=-1…….b=7……c=11 right

now you have to use the equation;-

y = -b (+ or -) root (b^2 – 4ac ) / 2a

y = -7(+or -) root { 49 – ( 4 * 1 * 11) } / 2 * 1

y = -7 ( + or – ) root ( 49 – 44 ) / 2

y = -7 ( + or – ) root 5 / 2

y=-7 ( + or -) 2,236 /2

now you going to have 2 right answer

y= 7+ 2,236 /2 =9,236 /2 =4,618

or y =7-2,236 /2 = 4,764 / 2 = 2,382

now from the equation # 1) x + y = 7 remove y and replace it with 4,618 so x + 4,618 = 7

then x = 7 – 4,618 = 2,382

do the same with y =2,382 …. x will be 4,618

now multiplay x * y = 2,382 * 4,618 =11.000076

so our answer is correct

x = 11 – your y