9 is the blank.
(a+b)^2 = a^2 + 2ab + b^2
a = x
b = 3
(x+3)^2 = x^2 + 6x + 9
Four times d to the third minus ten
Answer:
50 nickels, 20 quarters.
Step-by-step explanation:
System of equations (q = # of quarters, n = # of nickels):
<em>q + n = 70, 0.25q + 0.05n = 7.50</em>
the first equation can be changed to q = 70 - n, so we are able to <em>substitute q with 70 - n</em>.
So, it will look like <em>0.25*70 - 0.25n + 0.05n = 7.50</em>. This can be simplified to <em>0.2n = 10</em>, which means that n = 50.
Knowing that we can solve <em>q + 50 = 70</em>, which means that q = 20.
Recall to always convert the mixed fractions to "improper" fractions first,
x + 47 = 92. <--- x represents the number of 3rd graders
x +47-47 = 92-47
x=45
There are 45 third grader. Hope this helped!
