Jawapan

2016-08-14T21:20:20+08:00
(4x x 10) -  [(4 x x) + (1/2 x x x 10)]
=40x - (4x + 5x)
= 40x - 9x
= 31x
hope you understand :)
2016-08-14T21:34:26+08:00
The unknown x maybe will make you confuse, so Ichange it into y,ok

to find the shaded region, first you must find unshaded region because.. we know the formula for triangle and square/rectangle

the total figure's area - (triangle + square/ rectangle)

   [(6 + 4) x (4 + y) - [(1/2 x (6 + 4) x y) + (4 x y)]

= [10 x (4 + y)]  - (1/2 x 10 x y) + (4 x y)

= 40 y - (5y + 4y)

= 40y - 9y

= 31 y

then, now you can change the unknown to original unknown , x

= 31 x