Question

How do i solve this (give steps please)

Answer 1

Answer:

42x - 21 - 9x^2

Step-by-step explanation:

basically do the area of the whole rectangle then di the area of one of the empty spaces. then subtract the value of the empty space three times because there are three empty spaces.

Answer 2

Step-by-step explanation:

Let

$A_1$ = area of the small rectangle

$\:\:\:\:\:= x(3x + 1) = 3x^2 + x$

$A2$ = area of the large rectangle

$\:\:\:\:\:= (4x + 3)(10x - 7)$

$\:\:\:\:\:= 40x^2 - 28x + 30x - 21$

$\:\:\:\:\:= 40x^2 + 2x - 21$

Since there are 3 small rectangles, the area A of the shaded area is

$A = A_2 - 3A_1$

$\:\:\:\:= (40x^2 + 2x - 21) - 3(3x^2 + x)$

$\:\:\:\:= 40x^2 + 2x - 21 - 9x^2 - 3x$

$\:\:\:\:= 31x^2 - x - 21$