C looks like the smartest answer to go with.
Answer:
y = 32
Step-by-step explanation:
sqrt(2y) +3 = 11
Subtract 3 from each side
sqrt(2y) +3-3 = 11-3
sqrt(2y) = 8
Square each side
(sqrt(2y))^2 = 8^2
2y = 64
Divide by 2
2y/2 = 64/2
y = 32
The figure is a parallelogram so the facing sides have equal size which means :
DE = GF & DG = EF
-------------------------------------------------------------
DE = 3x - 1 , GF = 2x + 11
DE = GF ==》 3x - 1 = 2x + 11
subtract sides minus 2x
==》- 2x + 3x - 1 = - 2x + 2x + 11
collect like terms
==》 x - 1 = 11
add sides 1
==》 x - 1 + 1 = 11 + 1
==》 x = 12
-------------------------------------------------------------
As we found : DG = EF
DG = 2x - 3 So EF = 2x - 3
To find the size of EF, we need to put the value of x (which we found above) instead x.
EF = 2 × ( 12 ) - 3 ==》 EF = 24 - 3
==》 EF = 21
And we're done...
