Let's use J for James's age and A for Austin's age. The equations are:
J = A - 4
3J + A² = 28
Just plug (A - 4) in the place of J in the second equation. This gives you:
3(A - 4) + A² = 28
-->
A² + 3A - 12 = 28
-->
A² + 3A - 40 = 0
-->
(A - 5)(A + 8) = 0
-->
A = 5 or -8
-8 is nonsense, so Austin is 5 years old. Therefore, James is 1 year old.
Given that the mean is 55 inches and Dave is 57 inches, he would have increased the mean of the height in the stem-and-leaf plot that the students were making. This is however is also dependent upon the central tendency that was used, in this case the central tendency is mean or average.
Hello,
<span>We have that:
(4x+10)+(2x-1)=9x-15
</span>We solve the equation:
4x+10+2x-1=9x-15;
6x+9=9x-15;
6x-9x=-15-9;
-3x=-24;
3x=24;
<span>from which
</span>x=24:3=8
<span>Then:
DF=9x-15=(9</span>×8)-15=72-15=57
bye :-)
Answer/Step-by-step explanation (ac > b² or b² < ac.
)
A/c to question, we have to show:-
b² >ac in A.P ........ (1)
b² = ac in G.P .....(2)
b² < ac in H.P. ..... (3)
b = a+c/2 (A.P)
b = √ac ( G.P)
b = 2ac/a+c (H.P)
In A.P :
b² > ac = b² - ac
= (a+c/2)² - ac
= (a²+2ac+c²/4) - ac = a² + 2ac + c² - 4ac / 4
= a² - 2ac + c² / 4 = ( a - c ) ² / 4 > 0 Hence, b²>ac
In G.P:-
b = √ac
Hence, b² = ac
In H.P :- b² < ac = ac > b² = ac - b² = ac - ( 2ac / a+c)
= ac(a+c) - 2ac / a+c
= a²c + ac² - 2ac / a+c
= ac(2ac - 2) / a+c > 0
Hence, ac > b² or b² < ac.
