Answer:
(x,y,z) -> (2,4,1)
Step-by-step explanation:
-7x + y + z = -9
-7x + 5y - 9z = -3
7x - 6y + 4z = -6
Pick two pairs:
-7x + 5y - 9z = -3
7x - 6y + 4z = -6
and
-7x + y + z = -9
-7x + 5y - 9z = -3
Eliminate the same variable from each system:
-7x + 5y - 9z = -3
7x - 6y + 4z = -6
+ 5y - 9z = -3
- 6y + 4z = -6
<u><em>-1y - 5z = - 9</em></u>
-7x + y + z = -9
-7x + 5y - 9z = -3
-7x + y + z = -9
7x - 5y + 9z = 3
<u><em>-4y - 10z = -6</em></u>
Solve the system of the two new equations:
-1y - 5z = - 9 -> -4 ( -1y - 5z = - 9) -> 4y + 20z = 36
-4y - 10z = -6 -> -4y - 10z = -6 -> -4y - 10z = -6
10z = 30
Thus, z = 3
-4y - 10z = -6
-4y - 10(3) = -6
-4y - 30 = -6
-4y = 24
Thus, y = -6
Substitute into one of the original equations:
-7x + y + z = -9
-7x + (-6) + (3) = -9
7x + -3 = -9
7x = -6
x =
Answer:
D
Step-by-step explanation:
Matrix D represents 3 x 3 identity matrix.
Because all elements of principal diagonal are 1 and others are zero.
Answer:
The series is convergent answer ⇒ (a)
Step-by-step explanation:
* The series is -8/5 + 32/25 + -128/125 + ........
- It is a geometric series with:
- first term a = -8/5 and common ratio r = 32/25 ÷ -8/5 = -4/5
* The difference between the convergent and divergent
in the geometric series is :
- If the geometric series is given by sum = a + a r + a r² + a r³ + ...
* Where a is the first term and r is the common ratio
* If |r| < 1 then the following geometric series converges to a / (1 - r).
- Where a/1 - r is the sum to infinity
* The proof is:
∵ S = a(1 - r^n)/(1 - r) ⇒ when IrI < 1 and n very large number
∴ r^n approach to zero
∴ S = a(1 - 0)/(1 - r) = a/(1 - r)
∴ S∞ = a/1 - r
* If |r| ≥ 1 then the above geometric series diverges
∵ r = -4/5
∴ IrI = 4/5
∴ IrI < 1
∴ The series is convergent
Answer:
i think he reads like 30 pages per hour
Step-by-step explanation:
