Answer:
thxss for the points love
Step-by-step explanation:
kisses
The asnwer is 28. Since 7 is one of the factors,and 7+x=11,you would do 11-7 to find x. After doing 11-7 to find x (4),then you multiply 7 and 4 since they are the factors of the missing number. 7×4 is 28,therefore,you are the number 28.
A) 5/100 x 420 = 21
21 x 12 x 3= 756
420 x 12 x 3 = 15,120
15,120+756= 15,876
b) 4/100 x 420= $16.8
y = x³ + 3x² - x - 3
0 = x³ + 3x² - x - 3
0 = x²(x) + x²(3) - 1(x) - 1(3)
0 = x²(x + 3) - 1(x + 3)
0 = (x² - 1)(x + 3)
0 = (x² + x - x - 1)(x + 3)
0 = (x(x) + x(1) - 1(x) - 1(1))(x + 3)
0 = (x(x + 1) - 1(x + 1))(x + 3)
0 = (x - 1)(x + 1)(x + 3)
0 = x - 1 or 0 = x + 1 or 0 = x + 3
+ 1 + 1 - 1 - 1 - 3 - 3
1 = x or -1 = x or -3 = x
Solution Set: {-3, -1, 1}
Let's have a variable for each rate
x = account 1 (2.5% rate of interest)
y = account 2 (8% rate of interest)
The formulas we need are:
0.025x + 0.08y = 830 (amount of interest paid)
x + y = 20 000 (combined amount invested)
To solve we will use substitution (isolate for one variable and plugging into the other formula):
x + y = 20 000
x = 20 000-y
0.025x + 0.08y = 830
0.025(20 000-y) + 0.08y = 830
500-0.025y+0.08y=830
500+0.055y=830
0.055y=330
y=6000
Now that we know y (the 2nd account) = $6000 we need to find x. We do this by using the previous formula.
x = 20 000-y
x=20 000 - 6000
x=14000
She invested $14 000 at a 2.5% interest rate and $6 000 at a 8% interest rate.
*Notes:
the percentages were converted into decimal form
you check your answer by plugging the numbers back into the 2 formulas we made
