a computer manufacturing company would like to come up with a new laptop computer such that its monitor is 80 square inches smaller than the present ones. suppose the length of the monitor of the larger computer is 5 inches longer than its width and the area of the smaller computer is 70 inches square. What are the dimensions of the monitor of the larger computer?

Sagot :

try assigning 

Small:
x and y width and length
Large:
w and L width and length 

Develop expressions and equations:

xy=wl-80,l=w+5,xy=70

.
The two area equations give something to solve.
wl-80=xy=70
wl-80=70
wl=70+80
wl=150 
The area for the current large monitor. 

Substitute the formula transcribed for L into that area equation.
w(w+5)=150

(w+15)x(w-10)=0
The meaningful value is w=10
l=15.