Answer: Time it took her to get to the school is 0.6 hours
The distance of the school from their home is 27 miles
Step-by-step explanation:
Mrs Dang drove her daughter to school at the average speed of 45 miles per hour.
Let x miles = distance from the school to their home.
Distance = speed × time
Time = distance / speed
Time used in going to school will be
x/45
She returned home by the same route. This means that distance back home is also x miles.
She returned at an average speed of 30 miles per hour.
Time used in returning home from school will be x/30
x/45
If the trip took one half hour, then the time spent in going to school and the time spent in returning is 1 1/2 hours = 1.5 hours. Therefore
x/30 + x/45 = 1.5
(15x + 10x) /450 = 1.5
15x + 10x = 450 × 1.5 = 675
25x = 675
x = 675/25 = 27
Time it took her to get to the school will be x/45
= 27/45 = 0.6 hours
basically you treat y like a number and not a variable
Answer:
a is 4
b is 2y
c is -10y²+9
discriminant is 4(41y²-36)
Step-by-step explanation:
4x²+2xy-10y²+9=0
rewrite in standard form of a quadratic equation like ax² + bx + c = 0
4x²+2yx-10y²+9=0
basically you treat y like a number and not a variable
a is the number with the x²
right away we know a is 4 because of 4x²
b is the one with x so in this formula b is 2y
c is the number without the x which in this case is -10y²+9
discriminant is
b² - 4ac
(2y)²- (4)(4)(-10y²+9)
4y²-(16)(-10y²+9)
4y²-(16)(-10y²+9)
4y²+160y²-144
164y²-144 =
4(41y²-36)
Answer:
x² = 2x - 1
Step-by-step explanation:
x² + 1 = 2x
→ Minus 1 from both sides
x² = 2x - 1
