Answer: -12y²+7y²+20y-7
Step-by-step explanation:
Here, we need to use the concept of the FOIL method
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Given
(-3y+1)(4y²-y-7)
Expand Parenthesis using FOIL
-12y³+3y²+21y+4y²-y-7
Put like terms together
-12y³+(3y²+4y²)+(21y-y)-7
Combine like terms together
-12y²+7y²+20y-7
Hope this helps!! :)
Please let me know if you have any questions
Txydjjdykvyxjc 4th you'd. it's C
Answer:
Step-by-step explanation:
50% is but we're working with 64 units, not 100. So, we must find a number that represents 50 but in 64 units.
If you solve for x, you get:
It would be: 1/20 = x/16
x = 16/20
x = 4/5
So, it would be: 0.8 part to 16 part
Hope this helps!
Let the running speed if Daniel be r mph, then his biking speed is (r+3) mph, because "His running speed is 3 mph slower than his biking speed. "
let the time it took Daniel to get to his friend's house be t hours, then the time it took him to go to his house, from his friend,s house is (2-t) hours , because "His total running and biking time is 2 hours."
the main formula we need to solve this problem is:
Distance=Speed*Time
Daniels biking speed, (r+3) , is Distance/Time=2/(2-t)
so (r+3)=2/(2-t)
we also have the equation 5=rt, because
"Daniel leaves school and runs 5 miles to his friend's house"
we substitute t, by 5/r in the previous equation:
(r+3)=2/(2-t)
(r+3)=2/(2-5/r)
(r+3)(2-5/r)=2
2r-5+6-15/r=2
2r-1-15/r=0
multiply by r:
2r^2-r-15=0
the expression in the left side can be factorized as (2r+5)(r-3), so the equation becomes:
(2r+5)(r-3)=0,
and the roots are r=-5/2, which is not possible in our problem,
and r=3
Daniel's biking speed is r+3=3+3=6 (mph)
Answer: 6 mph