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
Step-by-step explanation:
The last step is a little wrong. Lemme show you:
x(x + 2) + (x + 2)
Imagine there is an invisible '1' infront of (x + 2) like this:
= x(x + 2) + 1(x + 2)
Now we can combine the like terms together:
= (x + 1)(x + 2)
This is the correct factorization.
Answer:
Yes
Step-by-step explanation:
There is a proportional relationship between x and y it's 5.
Think about it when x is 1 y is 5
When x is 2 y is 10
When x is 5 y is 25
When x is 7 y is 35
To get this for this question all you have to do is multiply x by 5 to get y.
That's how you know it's proportional.
Hope this helps!!!
Here is the work hope this helps!
X / (-4) + ( -63) = -45 <=> x / ( -4) = 63 - 45 <=> x / (-4) = 18 <=> x = 18 * (-4) <=> x = -72.
