Answer:
Commutative Property
Step-by-step explanation:
Additive Identity: If you add a real number to zero or add zero to a real number, then you get the same real number back.
Additive Inverse: When you add the same number but reversed sign, you get 0.
Commutative Property: a + b = b + a
Addition distributive property: a(b+ c) = ab + ac.
In this case, we use the commutative property:
27 + 15 + 3 + 5 = 27 + 3 + 15 + 5.
We know that 27 + 3 = 30 and 15 + 5 = 20, so we get 50 quickly using mental math.
Answer:
A book is worth $1 and a DVD is worth $12.
Step-by-step explanation:
The equations (2 unknowns and two equations, d is for a DVD and b is for a book):
For David: 3d+4b=40
For Anna: d+6b=18
Now multiply the second equation with -3 and add to the first equation:
3d+4b=40
−3d−18b=−54
Combined equation: −14b=−14 and b=1 (means that each book is worth $1).
Now for DVD price, use the second equation:
d=18−6 or d=12 (means that each DVD is worth $12).
A book is worth $1 and a DVD is worth $12.
Answer:
15
Step-by-step explanation:
x+5/36 = x/27
these are similar triangles
