<span>7r²+9=1
</span><span>the equation is contradictory, just to prove
7r</span>² + 9 = 1
7r² + 9 -1 = 0
7r² + 8 = 0
<span>We write the equation in the form of products of
</span>
7 * (r² + 8/7) = 0
<span>the product is equal to 0 when one of the factors is zero
</span>
7≠0 ∨ (r² + 8/7) = 0
r² ≠ - 8/7
<span>any number squared is not negative.
</span><span>We proved that none of the factors is not equal to zero , so the right side of the equation is not equal to the left . The equation is contradictory</span>
9514 1404 393
Answer:
Step-by-step explanation:
The system of equations can be written ...
n + d = 20 . . . . . . . . coins in the jar
5n +10d = 130 . . . . . value in cents
_____
Using the first equation, we can write an expression for n:
n = 20 -d
We can substitute this into the second equation:
5(20 -d) +10d = 130
100 +5d = 130 . . . . . . simplify
5d = 30 . . . . . . . . . . . . subtract 100
d = 6 . . . . . . . . . . . . divide by 5
n = 20-d = 14
The jar contains 14 nickels and 6 dimes.
I only know the first part (the expression which represents the amount Rita spent at the mall)
18.54x + 48
