Question 167677
Find the values of the variables:
one angle = 90 degrees
one angle = (2x-11)
one angle = (y+16)
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Since you have two unknowns  (x and y), you'll need two equations.
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equation 1: (as you say)
(2x-11)+(y+16) = 90
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since there are two congruent sides:
equation 2:
(2x-11)=(y+16)
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Solve equation 2 for x:
(2x-11)=(y+16)
2x-11 = y+16
2x = y+27
x = (1/2)(y+27)
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Plug the above into equation 1 and solve for y:
(2x-11)+(y+16) = 90
(2(1/2)(y+27)-11)+(y+16) = 90
y+27-11+y+16 = 90
2y+27-11+16 = 90
2y+16+16 = 90
2y+32 = 90
2y = 58
y = 29
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Plug it back into equation 2 to find x:
(2x-11)=(y+16)
(2x-11)=(29+16)
2x-11=45
2x=56
x = 28
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solution: 
x is 28
y is 29