Answer:
Step-by-step explanation:
Direct variation has the form y=kx, given k=7 and x=20
y=7(20)=140
Answer:
12
Step-by-step explanation:
You bring all xs on one side then you solve as quadratic analysis.
![x + 8 + {x}^{2} - 4x - 12 = 0](https://tex.z-dn.net/?f=x%20%2B%208%20%2B%20%20%7Bx%7D%5E%7B2%7D%20%20-%204x%20-%2012%20%3D%200)
![{x}^{2} - 3x - 4 = 0](https://tex.z-dn.net/?f=%20%20%7Bx%7D%5E%7B2%7D%20-%203x%20-%204%20%3D%200)
so you can simplify into
![(x + 1)(x - 4) = 0](https://tex.z-dn.net/?f=%28x%20%2B%201%29%28x%20-%204%29%20%3D%200)
*Note that here 4 took the negative sign and 1 took the positive sign, as you want to numbers that if multiplied will give -4 and when added will give -3, and these are (-4 and 1)*
so now you can simply say that, for the equation to equal 0, x should be -1 or 4.
You can always substitute to make sure of your calculations.
Hope this helps.
Answer:
its c or #3
Step-by-step explanation:
<span>2x^2 - 8x - 90
= 2 (x^2 - 4x - 45)
= 2 (x - 9)(x + 5)
so
x - 9 = 0; x = 9
x + 5 = 0; x = -5
solutions -5 and 9
answer
</span><span>B)-5</span>
<span>D)9</span>