Find the difference in area between a rectangle measuring 35 cm by 12 cm and a triangle whose base and height are 22 cm and 32 cm respectively.

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

8p+(-9)

(-9)3p+5p and you can swith em around