let x be the number of acres of corn
let y be the number of acres of wheat
corn and wheat will take up 180 acres
x+y=180
3 times corn than wheat
x=3y
2 equations 2 unknown
x+y=180
x=3y
solving using substitution
x+y=180
substitute for x
x+y=180
(3y)+y=180
3y+y=180
4y=180
divide by 4 to both sides
4/4 y = 180/4
y=45
45 acres of wheat planted
using 2nd equation to find x
x=3y
x=3(45)
x=135
135 acres of corn planted