Answer:
x = 6 x = -7
Step-by-step explanation:
Subtract 12 from each side:
x^2 + x - 30 - 12 = 12 - 12
Simplify:
x^2 + x - 42 = 0
Solve with quadratic formula using both +/- after the first -1:
x = 
Simplify:
x = 6
x = -7
Answer:
The competing company is better
7 for 25.90 vs. 7 for 25.83
Step-by-step explanation:
Since it's 3 for 11.07
we need to see how much higher the price will get at 7, so divde 11.07 by 3 then double the price.
3.69 per box for competing company
11.07*2 = 22.14
22.14 + 3.69= 25.83
4x - 5y = -15
y = -3x + 22
Plug in your y= equation into the y variable in the other equation
4x - 5 (y) = -15
^^
y = (-3x + 22) = -15
4x - 5 (-3x + 22) = -15
Distribute
4x + 15x - 110 = -15
Combine like terms and add 110 over to -15
19x = 95
Then, divide the whole equation by 19
x = 5
Then, plug in your x into your y= equation
y = -3 (5) + 22
y = -15 + 22
y = 7
<em><u>x = 5</u></em>
<em><u>y = 7</u></em>
<em><u>(5, 7)</u></em>
Answer:
then her brother would be 12 years old
