Answer:
9
Step-by-step explanation:
7r+18=r²
r²-7r-18=0
factorizing
r²+2r-9r-18=0
r(r+2)-9(r+2=0
(r-9)(r+2)=0
r-9=0
r=9
check
(r²)=(9*9)=81
7r+18=7(9) + 8=81
Answer:
(1, –5)
Step-by-step explanation:
It is relatively easy to try the offered solutions to see what works.
<u>(1, -5)</u>
3(1) +10(-5) = -47 . . . true
5(1) -7(-5) = 40 . . . true
(1, -5) is the solution
_____
As a check, you can try some of the other choices:
<u>(1, 5)</u>
3(1) +10(5) ≠ -47
<u>(-1, -5)</u>
3(-1) +10(-5) ≠ -47
<u>(-1, 5)</u>
3(-1) +10(5) ≠ -47
None of the other choices works in the first equation, so they're not the solution.
The total value is:
5. 5 x 10 ^5 * 23 x 10^3 =
= $126.5 * 10^8 =
= $1.265 x 10^10
Answer: B )
Eli will finish first.
Use 8/10 and 10/12. This represents how many spring rolls over how many minutes. Make your equations like this: 8/10 = 40/x and 10/12 = 40/x. Find x, which will give you the minutes it takes them to make 40 rolls.
You get x = 50 for the first one and x = 48 for the second. Nora makes 40 rolls in 50 minutes, and Eli makes 40 rolls in 48 minutes. Eli is faster.
Hope this helped! Please mark me brainliest!
