Step-by-step explanation:
let jon age be x
dad age is 2 of x i.e 2x
grandpa age is 7 + 3(x)
The sum of jon dad and grandpa age is 145 i.e
x + 2x + (7+3x) = 145
3x +. 7 + 3x = 145
6x = 145- 7
6x = 138
divide both sides by 6
x = 23
jon age is 23
while
grandpa age is
7 + 3(x)
7 + 3(23)
7 + 69
76.
Answer:
Value of x = 19.42 unit (Approx)
Step-by-step explanation:
Given:
Base = 6 unit
Angle θ = 72°
Find:
Value of x
Computation:
Cos θ = base / Hypotenuse
Cos 72° = 6 / x
0.3090 = 6 / x
x = 19.4174
Value of x = 19.42 unit (Approx)
Answer: A
Step-by-step explanation:
Take 2 equations that make one of their letters disappear, and add them up:
2x + y + z = 1
x - y + 4z = 0
------------------------
3x + 5z = 1
Do the same with another 2 equations in which the letter, in this case y, can be removed. If you can't, take 2 of 3 equations and equal the value of the letter to make it eliminable.
x - y + 4z = 0
x + 2y - 2z = 3
Since we can't eliminate y, we have multiply as necessary to make it eliminable:
2 (x - y + 4z = 0)
= 2x - 2y + 8z = 0
add all up:
2x - 2y + 8z = 0
x + 2y - 2z = 3
-----------------------------
3x + 6z = 3
Now we've gone from a 3-variable equation to a 2-variable equation.
3x + 5z = 1
3x + 6z = 3
We can solve again by elimination; to get rid of z, for example, we cross multiply. the upper equation by 6 and the lower equation by 5. However, we have to make one of them negative in order to make them eliminable.
6 (3x + 5z = 1)
-5 (3x + 6z = 3)
----------------------------
18x + 30z = 6
-15x - 30z = -15
---------------------------
3x = - 9
Solving for x;
x = 
x = - 3
After finding one variable, we can use our 2-variable equations to find the next variable:
3x + 5z = 1
3 (-3) + 5z = 1
- 9 + 5z = 1
5z = 1 + 9
5z = 10
z = 
z = 2
Having found these 2 variables, we can put them into one of our main 3-variable equations to find the last one:
2x + y + z = 1
2(-3) + y + 2 = 1
- 6 + y + 2 = 1
y - 4 = 1
y = 1 + 4
y = 5
And you've found all the variables in the equation; to prove if they're correct or not, you can replace them in any of the main equations and the result should be equal to each other:
x + 2y - 2z = 3
-3 + 2(5) - 2(2) = 3
- 3 + 10 - 4 = 3
10 - 7 = 3
3 = 3
Y = -1/3x + 2
Explain: subtract 3x from 18, which will get you -3x + 18.
Next, get 9y and divide it by everything so it’ll look like 9y = -3x + 18
-——-————
9y
and you’ll get y = -1/3x + 2
Hope this helped
Answer:

Step-by-step explanation:
Use the formula:

We have:

Substitute:
