2x + 5y = 25
y = 3x + 22

x = - 5

Step-by-step explanation:

2x + 5y = 25

Replace y by the equation given

2x + 5 (3x + 22) = 25

Solve.

2x + 15x + 110 = 25

17x + 110 = 25

17x + 110 - 110 = 25 - 110

17x = - 85

17x / 17x = - 85 / 17

= - 5

x = - 5

$53.50

step-by-step explanation:

you have to subtract the amount of money chuck earned ($72.50) by the cost of the gas for the mower ($11.25) and the new string for the trimmer he bought ($7.75).

72.50-11.25=61.25

and then subtract $61.25 by the second thing he bought (the new string for the trimmer)

61.25-7.75=53.5

so in total it's $53.50 (53 dollars and 50 cents)

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for