When a number is decreased by 18, the result is 14. what is the number
2 answers:
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Basically you're solving for both variables here.
I prefer elimination method so that is what I used.
I started off by multiplying each equation in order to get one of the variables at the same value so it would be possible to cancel it out.
Multiplying the first equation by 3 gave me,
12x + 15y = 69
Then I multiplied the second equation by 4,
-12x + 28y = -56
As you can see, it's not possible to cancel out the x variable.
12x + 15y = 69
+(-12x + 28y = -56)
_____________
13y = 13
Then just solve for y which gives you -1.
After you have one variable solved simply insert it into one of the original equations to find the other variable.
4x + 5(-1) = 23
4x - 5 = 23
4x = 28
x = 7.
And there you have it! Hope this helped!
I prefer elimination method so that is what I used.
I started off by multiplying each equation in order to get one of the variables at the same value so it would be possible to cancel it out.
Multiplying the first equation by 3 gave me,
12x + 15y = 69
Then I multiplied the second equation by 4,
-12x + 28y = -56
As you can see, it's not possible to cancel out the x variable.
12x + 15y = 69
+(-12x + 28y = -56)
_____________
13y = 13
Then just solve for y which gives you -1.
After you have one variable solved simply insert it into one of the original equations to find the other variable.
4x + 5(-1) = 23
4x - 5 = 23
4x = 28
x = 7.
And there you have it! Hope this helped!
5. Answer: see explanation
<u>Step-by-step explanation:</u>
If the roots are m and 3m, then x = m and x = 3m
⇒ x - m = 0 and x - 3m = 0
⇒ (x - m)(x - 3m) = 0
⇒ x² - 4mx + 3m² = 0
Since x² + px + q = 0 then p = -4m and q = 3m²
3p² = 3(-4m)² 16q = 16(3m²)
= 3(16m²) = 48m²
= 48m²
3p² = 48m² = 16q ⇒ 3p² = 16q
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6. Answer: 8 or 18
<u>Step-by-step explanation:</u>
The Area of the entire rectangle (A = L × w) is 12 × 10 = 120
The Area of the shaded region is 72, so the Area of the non-shaded region is 120 - 72 = 48.
There are two non-shaded triangles.
- Bigger non-shaded Δ: L = 12-x, w = 10 ⇒
- Smaller non-shaded Δ: L = x, w = x ⇒
Combine the Areas of both triangles and set it equal to the Area of the non-shaded region:
Area of ΔBEF: