Answer:
Rectangular book--
two 8 1/2 sides
two 9 1/4 sides
8 1/2*2=17
9 1/4*2=18 1/2
17+18 1/2= 35 1/2
The perimeter of the textbook is 35 1/2 inches or 35.5 inches.
-this is not mine btw creds to sunflowerem :))
So it is an isosceles triangle that means that the bottom two angles are equal...
so
40 = 5x
divide both sides by 5 and you get 8
now the triangle angles add up to 180
we make an equation out of it...
(2y + 20 ) + ( 5(8)) + 40 = 180
2y + 20 + 40 + 40 = 180
combine like terms
2y + 100 = 180
so subtract 100 from both sides
2y = 80
divide by 2 to isolate the variable
y = 40
You are correct!!! :)
Combine like terms
-7y² + 6y² - 2y² = -3y²
4y + (-5y) - (-9y) = 4y - 5y + 9y = 8y
9 + 9 - (-2) = 9 + 9 + 2 = 20
-3y² + 8y + 20 is your answer
hope this helps
