Answer:
x^2 -7x-18
Step-by-step explanation:
(x-9)(x+2)
FOIL
first x*x = x^2
outer 2x
inner -9x
last -9*2 =-18
Add together
x^2 +2x-9x-18
Combine like terms
x^2 -7x-18
Do a proportion. X/7/8=1/1/2. 7/8 x 1= 7/8. Now do 7/8 divided by 1/2. To do this multiply 7/8 by the reciprocal of 1/2 which is 2/1. 7 x 2= 14 and 8 x 1=8. Improper fraction is 14/8. It is 1 6/8 as a mixed number which is simplified to 1 3/4. Answer is 1 3/4
Let x be the number of weeks; therefore, the two linear equations are

Where T stands for the punches on the tea punch card and C for the punches on the coffee punch card.
Solving by substitution. Set T=C, then

Thus, substitute the value of x=3 into the first equation,

Thus, after 3 weeks, Josiah will have the same number of punches on each card, and he will have 23 punches on each card.
12
since the difference of the first and third value is ten, each value is five more than the previous value