Answer:
D. There is no mistake.
Step-by-step explanation:
The following lines show the process of factorization by using common factor.
<u>Line 1:</u>
In line 1, the equation is given and is completely fine.

The only thing missing was equate to zero, but the options below talk about correct factors only, therefore this can't be considered as a mistake and can be ignored completely.
<u>Line 2:</u>
In line 2, the terms are grouped, from which we can factor out common terms.

This is also fine.
<u>Line 3:</u>
In line 3, the common term y is taken out from group 1 and 2 from other group.

which is exactly what is given in line 3.
<u>Line 4:</u>
In line 4 the common factors can be seen and easily split into 2 factors.

which is exactly what is given in line 4.
Options:
A. The grouping is correct in line 2. So this option is does not hold.
B. Common factor was factored correctly from group 1. So this option does not hold.
C. Common factor was factored correctly from group 2. So this option does not hold.
D. There is no mistake. This is correct. Thus we choose this option as correct answer.
Answer:
The best estimate for 43x78 is 40x80
Step-by-step explanation:
43 rounded to the nearest ten is 40.
78 rounded to the nearest ten is 80.
The answer to 40x80 is 3200
We are given the equations:
<span>5 x + 11 y = 49 -->
eqtn 1</span>
<span>u = 3 x^2 + 6 y^2 -->
eqtn 2</span>
Rewrite eqtn 1 explicit to y:
11 y = 49 – 5 x
<span>y = (49 – 5x) / 11 -->
eqtn 3</span>
Substitute eqtn 3 to eqtn 2:
u = 3 x^2 + 6 [(49 – 5x) / 11]^2
u = 3 x^2 + 6 [(2401 – 490 x + 25 x^2) / 121]
u = 3 x^2 + 14406/121 – 2940x/121 + 150x^2/121
u = 4.24 x^2 – 24.3 x + 119.06
Derive then set du/dx = 0 to get the maxima:
du/dx = 8.48 x – 24.3 = 0
solving for x:
8.48 x = 24.3
x = 2.87
so y is:
y = (49 – 5x) / 11 = (49 – 5*2.87) / 11
y = 3.15
Answer:
<span>George will choose some of each commodity but more y than
x.</span>
A negative exponent means to move the decimal point to the left the number of the exponent.
10^-1 you would move the decimal 1 place to the left.
5.401 x 10^-1 = 0.5401