-7(x + 1) - 3 = -8x + 11

=> - 7 ( x + 1 ) - 3 = - 8x + 11

=> - 7x + ( - 7 ) - 3 = - 8x + 11

=> - 7x - 7 - 3 = - 8x + 11

=> - 7x - 10 = - 8x + 11

By putting the the variable terms on one side & constant terms on the other side we have ,

=> - 7x + 8x = 11 + 10 eq( 1 )

=> x = 21

Hence , x = 21

By substituting the value of x we got in the above solution . If LHS = RHS we have ,

➩ - 7 ( 21 ) + 8 ( 21 ) = 11 + 10

By taking common in RHS

➩ ( 21 ) ( - 7 + 8 ) = 11 + 10

➩ 21 × 1 = 21

➩ 21 = 21

LHS = RHS

Hence , verified

hope this !

step-by-step explanation:

d = distance between moon and sun, which in this problem is the hypotenuse of a right triangle.  

the distance y is the side opposite to angle x in the right triangle.   use the definition of the sine function from basic trigonometry.

sin(x) = y/d ⇒

d = y/sin(x)

it would open into a square depending on the type of envelope i’m not sure about the second part