Decomposition factor. 9 (a + b) & # 178; - 16 (a-b) & # 178;

Decomposition factor. 9 (a + b) & # 178; - 16 (a-b) & # 178;

solution
9(a+b)²-16(a-b)²
=[3(a+b)]²-[4(a-b)]²
=[3(a+b)-4(a-b)][3(a+b)+4(a-b)]
=(7b-a)(7a-b)

A & # 178; + B & # 178; = 9 16 / A & # 178; + 15 / B & # 178; = 1

16/a²+15/b²=1
16b²+15a²=a²b²
9*15+b²=a²b² ①
A & # 178; + B & # 178; = 9 A & # 178; = 9-b & # 178; substitute into ① to get
135+b²=(9-b²)b²
(b²)²-8b²+135=0
(b²-4)²+119=0
unsolvable
a²/16+b²/15=1 ①
A & # 178; + B & # 178; = 9 A & # 178; = 9-b & # 178; substitute into ① to get
(9-b²)/16+b²/15=1
b²/(15*16)=1-9/16=7/16
b²=7*15 a²=9-b²=?
b=±√105

One ninth A & # 178; + one sixteenth B & # 178; + one fourth C & # 178; + one sixth AB + one fourth BC + one third CA = [() + ()] &# 178;

A & # 178 / / 9 + B & # 178 / / 16 + C & # 178 / / 4 + AB / 6 + BC / 4 + Ca / 3 = (A / 3) & # 178; + (B / 4) & # 178; + (C / 2) & # 178; + 2 × A / 3 × B / 4 + 2 × B / 4 × C / 2 + 2 × C / 2 × A / 3 = (A / 3 + B / 4 + C / 2) & # 178; this is my conclusion after meditation. If you can't ask me, I will try my best to help you solve

What can the algebraic formula 2x + 3 represent? Combined with the actual life, give two examples that can use this algebraic formula to describe the quantitative relationship
do somebody a favour

Club A is x, Club B is an honor club, the number of which is twice as many as that of club a and three more
Party A and Party B are employees of the same company. Party A is a new employee, and the daily quantity is x pieces. Party B is the predecessor of Party A, and the quantity is twice as much as that of Party A, and there are more than three pieces

The - 1 power of 3 + the - 2 power of 3... How much does it add to the 1-n power of 3

If s = 1 / 3 * (1-1 / 3 ^ (n-1)) / (1-1 / 3) = 1 / 2 * (1-1 / 3 ^ (n-1))

Solve the equation: the fruit store shipped 300 kg of apples and pears, the mass of apples is 1.5 times that of pears, and the apples and pears each have several thousand grams

Set pear x kg, apple 1.5x kg
X+1.5X=300
2.5X=300
X=300/2.5
X=120
Pear 120 kg, apple 180 kg

The master and the apprentice produce a batch of parts together. The master has finished 1 / 2 of the total number (this is one and half), less than 10. The apprentice has finished the master's production
Half of the quantity, there are 55 left. How many parts do the master and apprentice share?

55 △ (1-1 and 2 moleculars 1)
=55 △ 1 / 2
=110

In the AC circuit of capacitor element, the terminal voltage of capacitor element is in phase____ In current (multiple choice)
A. Lead B. lag C. equal D. uncertainty

B behind, 90 degrees behind

During the holiday, Xiao Ming and his classmates went to an island to explore treasure. According to the treasure map, after landing, they walked 8 kilometers east, 2 kilometers north, 3 kilometers west after encountering obstacles, and then turned 6 kilometers north. After walking only 1 kilometer, they found the treasure. What is the distance between landing point a and treasure burial point B______ Kilometers

When passing through point B, make BC ⊥ AC, and AC and BC intersect at point C, with ⊥ ACB = 90 ° from the figure, AC = (8-3 + 1) km = 6 km, BC = (2 + 6) km = 8 km, in RT △ ABC, AC = 6 km, BC = 8 km, then according to Pythagorean theorem, ab = ac2 + BC2 = 10 km, so the answer is 10

Linear algebra, how to quickly determine whether a matrix is invertible

1. Determinant is not equal to 0
2. The system AX = 0 has only 0 solution
3. Rank = order
4. All eigenvalues are not 0
5. Linear independence of row vector group
6. The column vector group is linearly independent
7. There is another B such that ab = Ba = e (definition)