"He starts by sprinting 100 yards", so the first term is a_1 = 100
The common difference is d = 5 because he's adding 5 yards per day. The "21 days" info isn't going to be used at all
So because a_1 = 100 and d = 5, this means
a_n = a_1 + d*(n-1)
a_n = 100 + 5*(n-1)
a_n = 100 + (n-1)*5
Answer is choice D
Thank you so much that is very sweet of you
Substitute any number in for x and solve for y. Say that x=1.
y=5(1)-7
y=5-7
y=-2
The ordered pair would be (1,-2).
X = 9
y = 6
Step by step:
Divide 15 by 2: 15 ÷ 2 = 7.5
Subtract 0.5 from 7.5 (this will later be added back): 7.5 - 0.5 = 7
Subtract 1 from 7 (she wants to buy at least 2 more children books): 7 - 1 = 6
Subtract 6 from 15 (6 being the number of puzzle books, 15 being the total number of items): 15 - 6 = 9 (number of children books)
Our two binomials are (X-5)(X-7)
If we FOIL those two terms [x*x = x2; x*-7 = -7x; x*-5 = -5x; -5*-7 = 35] and combine the like terms, we're left with one of many quadratic function
Answer
x2-12x+35
