X=2
El mejor programa para que te ayuda es Math,
way
<span>RS= 8y + 4, ST = 4y + 8, and RT = 36
RS + ST = RT
</span>8y + 4 + 4y + 8 = 36
12y + 12 = 36
12y = 24
y = 2
answer
y = 2 (first choice)
Another way is to note that there are <span><span>(<span>104</span>)</span><span>(<span>104</span>)</span></span> (“10 choose 4”) ways to select 4 balls from a collection of 10. If 4 of those 10 balls are “special” in some way (in this case, “special” = “red”), then the number of ways to choose 4 special balls is <span><span>(<span>44</span>)</span><span>(<span>44</span>)</span></span>. (The factor of <span><span>(<span>60</span>)</span><span>(<span>60</span>)</span></span> is included to convey that, after choosing 4 special balls, we choose none of the 6 non-special balls.) This line of reasoning gives the second expression.