Answer:(7x3)+(4x24)=117
Step-by-step explanation:
Since he needs 3 feet of wood and it is 7 dollar per foot, you need to multiply 7 by 3. Since he needs 4 pieces of glass and its 24 dollars per glass multiply 4 by 24. Add the products. Ur done!
5. The 5th figure will have 30 tiles.
6. The 6th figure will have 42 tiles.
7. The pattern is non-linear (quadratic).
8. The 20th figure can be made with 420 tiles.
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The Nth figure is made with n*(n+1) tiles. To answer question 8, you must solve
.. n(n +1) = 420
.. n^2 +n -420 = 0
.. (n +21)(n -20) = 0
.. n = 20 or -21 . . . . the negative solution is extraneous
Um.. Both of those equations are the exact same. Divide both sides of the first equation by 6. You get:

That is the exact same as the second equation. This system has an infinite number of solutions. 5x - 7y = -1 is a line, so basically every point on that line is a solution to the system.
For example,

and

would work, but so would

and
Answer:
because they made a mistake