Answer:
7 years
Step-by-step explanation:
Given that:
Let Richard's age = x
Elder sister's age = 2x
Youngwr sister's age = x - 2
Product of sisters ages = 70
2x * (x - 2) = 70
2x² - 4x = 70
2x² - 4x - 70 = 0
x² - 2x - 35 = 0
x² - 7x + 5x - 35 = 0
x(x - 7) +5(x - 7) = 0
(x - 7) or (x + 5) = 0
x = 7 or x = - 5
X can't be negative
Hence, x = 7
Richard is 7 years
Answer:
All the members of a construction crew work at the same pace. Four of them working together are able to pour concrete foundations in 32 hours.
Step-by-step explanation:
Answer:
-13
-10
Step-by-step explanation:
A x = B
To find X
A ^ -1 A x = A ^ -1 B
x = A^ -1 B
x = -3/2 -5/2 2
-1 -2 4
Across times down
-3/2 * 2 + -5/2 *4 = -13
-1 *2 -2 * 4 = -10
The matrix is
-13
-10
Answer
Step-by-step explanation:
One solution :
x = -1/3 = -0.333
Rearrange:
Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :
-5*(3*x+1)+4*x-(10*x+2)=0
Step by step solution :
Step 1 :
Equation at the end of step 1 :
((0 - 5 • (3x + 1)) + 4x) - (10x + 2) = 0
Step 2 :
Step 3 :
Pulling out like terms :
3.1 Pull out like factors :
-21x - 7 = -7 • (3x + 1)
Equation at the end of step 3 :
-7 • (3x + 1) = 0
Step 4 :
Equations which are never true :
4.1 Solve : -7 = 0
First, a bit of housekeeping:
<span>The meaning of four consecutive even numbers is 15. Wouldn't that be "mean," not meaning? Very different concepts!
The greatest of these numbers is _______ a^1
"a^1" means "a to the first power. There are no powers in this problem statement. Perhaps you meant just "a" or "a_1" or a(1).
The least of these numbers is ______a^2.
No powers in this problem statement. Perhaps you meant a_2 or a(2)
In this problem you have four numbers. All are even, and there's a spacing of 2 units between each pair of numbers (consecutive even).
The mean, or arithmetic average, of these numbers is (a+b+c+d) / 4, where a, b, c and d represent the four consecutive even numbers. Here this mean is 15. The mean is most likely positioned between b anc c.
So here's what we have: a+b+c+d
------------- = 15
4
This is equivalent to a+b+c+d = 60.
Since the numbers a, b, c and d are consecutive even integers, let's try this:
a + (a+2) + (a+4) + (a+6) = 60. Then 4a+2+4+6=60, or 4a = 48, or a=12.
Then a=12, b=14, c=16 and d=18. Note how (12+14+16+18) / 4 = 15, which is the given mean.
We could also type, "a(1)=12, a(2)=14, a(3) = 16, and a(4) = 18.
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