Solve the following system using substitution or elimination: The sides of a triangle have measures of x, x, and y, and the perimeter of the triangle is 46. The measure y is 4 centimeters longer than the measure x.

Question

Solve the following system using substitution or elimination:  The sides of a triangle have measures of x, x, and y, and the perimeter of the triangle is 46. The measure y is 4 centimeters longer than the measure x.

hero · Answer

2x + y = 46
y = x + 4

anonymous · Answer

y=x+4, 2x+y = 46 are the two simultaneous equations that you can derive from the information. Next use your favourite method of solving them (out of elimination or substitution).

anonymous · Answer

x=14
y=18

anonymous · Answer

2x + (x+4) = 46 ---> 3x = 42 ---> x=14

anonymous · Answer

substitution

hero · Answer

Okay, I'll use my favorite method: 

2x + y = 46
y = x + 4

y = 46 - 2x

y = y

x + 4 = 46 - 2x
3x = 42
x = 42/3
x = 14
y = 18

anonymous · Answer

then put x=14 into either of your starting equations to get y=18