By substitution is how to solve
2x-3y=21
y=3-x
2x-3(3-x)=21
2x-9+3x=21
5x=30
x= 6
now substitute our x value into y=3-x
so we get
y=3-6 = -3
so x=6 and y=-3 hope this helps!!!!! Thank you!
Answer:
Her speed on the summit was 35 mph.
Step-by-step explanation:
Her speed on the summit was "x" mph while her speed while climbing was "x - 10" mph. The distance she rode uphill was 55 miles and on the summit it was 28 miles. The total time she explored the mountain was 3 hours. Therefore:
time uphill = distance uphill / speed uphill = 55 / (x - 10)
time summit = distance summit / speed summit = 28 / x
total time = time uphill + time summit
3 = [55 / (x - 10)] + 28 / x
3 = [55*x + 28*(x - 10)]/[x*(x - 10)]
3*x*(x - 10) = 55*x + 28*x - 280
3x² - 30*x = 83*x - 280
3x² - 113*x + 280 = 0
x1 = {-(-113) + sqrt[(-113)² - 4*(3)*(280)]}/(2*3) = 35 mph
x2 = {-(-113) - sqrt[(-113)² - 4*(3)*(280)]}/(2*3) = 2.67 mph
Since her speed on the uphill couldn't be negative the speed on the summit can only be 35 mph.
2nd one: 2 rectangles can have thr same area but have different perimeters.
Answer:
1:3
Step-by-step explanation:
There are 3 adults per 1 child at the book fair. I think this is right but im not 100% sure :)
