Answer:
option B. they are complementary
Step-by-step explanation:
Answer: Each screensaver costs $2 and each Otterbox costs $7.
Step-by-step explanation:
Let x = Cost of each screensaver and y = cost of each Otterbox.
As per given, 4x+3y=29 (i)
6x +2y = 26 (ii)
Divide both sides of (i) by 2 and the multiply it by 3 on sides , we get
9x+3y=39 (iii)
Eliminate (i) from (iii) , we get
5x = 10
⇒ x = 2 [Divide both sides by 5]
Put value of x in (i), we get
4(2)+3y=29
⇒ 8+3y= 29
⇒ 3y= 21
⇒ y =7 [Divide both sides by 7]
Hence, Each screensaver costs $2 and each Otterbox costs $7.
just like the previous one, we sum the sides to get the perimeter.

Answer:
77.
Proved
78.
Proved
79.
Proved.
80.
Proved.
Step-by-step explanation:
77. Left hand side
=
=
=
{Since we know,
}
=
= Right hand side (Proved)
78. Left hand side
=
=
{Since
}
=
= Right hand side (Proved)
79. Left hand side
=
=
{Since
}
=
= Right hand side
80. Left hand side
=
=
{Since
}
=
=
= Right hand side. (Proved)