Step-by-step explanation:
1st digit is 1 number (1)
2nd digit is (3,4,5) so it's 3 numbers
third digit is (6,7,8,9) is it's 4 numbers
last 7 digits is 10 (0,1,2,3,4,5,6,7,8,9)
multiply
1*3*4*10=120
so answer is 120 phone numbers
The quadratic equations and their solutions are;
9 ± √33 /4 = 2x² - 9x + 6.
4 ± √6 /2 = 2x² - 8x + 5.
9 ± √89 /4 = 2x² - 9x - 1.
4 ± √22 /2 = 2x² - 8x - 3.
Explanation:
- Any quadratic equation of the form, ax² + bx + c = 0 can be solved using the formula x = -b ± √b² - 4ac / 2a. Here a, b, and c are the coefficients of the x², x, and the numeric term respectively.
- We have to solve all of the five equations to be able to match the equations with their solutions.
- 2x² - 8x + 5, here a = 2, b = -8, c = 5. x = -b ± √b² - 4ac / 2a = -(-8) ± √(-8)² - 4(2)(5) / 2(2) = 8 ± √64 - 40/4. 24 can also be written as 4 × 6 and √4 = 2. So x = 8 ± 2√6 / 2×2= 4±√6/2.
- 2x² - 10x + 3, here a = 2, b = -10, c = 3. x =-b ± √b² - 4ac / 2a =-(-10) ± √(-10)² - 4(2)(3) / 2(4) = 10 ± √100 + 24/4. 124 can also be written as 4 × 31 and √4 = 2. So x = 10 ± 2√31 / 2×2 = 5 ± √31 /2.
- 2x² - 8x - 3, here a = 2, b = -8, c = -3. x = -b ± √b² - 4ac / 2a = -(-8) ± √(-8)² - 4(2)(-3) / 2(2) = 8 ± √64 + 24/4. 88 can also be written as 4 × 22 and √4 = 2. So x = 8 ± 2√22 / 2×2 = 4± √22/2.
- 2x² - 9x - 1, here a = 2, b = -9, c = -1. x = -b ± √b² - 4ac / 2a = -(-9) ± √(-9)² - 4(2)(-1) / 2(2) = 9 ± √81 + 8/4. x = 9 ± √89 / 4.
- 2x² - 9x + 6, here a = 2, b = -9, c = 6. x = -b ± √b² - 4ac / 2a = -(-9) ± √(-9)² - 4(2)(6) / 2(2) = 9 ± √81 - 48/4. x = 9 ± √33 / 4 .
Answer:
33beacuse you i have -90×+60=9×6=369-63
Decimals that contain a zero in the tenth position can be thought of as a fraction over 100 as the tenth isn't occupied and the hundredth correlates to the 100 as a denominator. The same goes for a number with the tenth position occupied. These decimals would be put over 10 as they are occupying that position in the decimal.
Answer:
Concept: Caclulating Standard Variables
- We have a five number summary which is more than enough information to calculate our mean.
- The mean is the sum of all the numbers divided by the nth number of numbers.
- Note that we can only find a rough estimation not the EXACT value
- We do (min +max + 2(Q1+median+Q3))/8
- Now let's plug in our values!
- (0+85.3+2(8.4+17.4+30.9))/8
- Which gives us option B
- Hope this helps, give brainlist
