The answer is 5. Measure r and t are congruent. Measure r is 20 so measure t is also 20. So by dividing 20 by 4 you get 5.
System of Linear Equations entered :
[1] 5x - 6y = 7
[2] 6x - 7y = 8
Graphic Representation of the Equations :
-6y + 5x = 7 -7y + 6x = 8
Solve equation [2] for the variable x
[2] 6x = 7y + 8
[2] x = 7y/6 + 4/3
// Plug this in for variable x in equation [1]
[1] 5•(7y/6+4/3) - 6y = 7
[1] - y/6 = 1/3
[1] - y = 2
// Solve equation [1] for the variable y
[1] y = - 2
// By now we know this much :
x = 7y/6+4/3
y = -2
// Use the y value to solve for x
x = (7/6)(-2)+4/3 = -1
let x represent granddaughter and x +2 for grandson and together they = 12
so then we have the equation of x+2+x = 12
combine like terms 2x +2 =12
-2 from both sides to isolate x
2x=10 divide both sides by 2 to get x by itself
so we get x = 5 then add 2 +5=7
so grandson is 7 and granddaughter is 5