V2+4v-21=0 (solve by factoring)

(v + 7)(v -3)

Step-by-step explanation:

(v +7)(v -3)

v x v = v^2

v x -3 = -3v

7 x v = 7v

7 x -3 = -21

v^2 -3v +7v -21 = v^2 +4v -21 = 0

The answer is (v - 3)(v + 7).

Step-by-step explanation:

First, you have to elaborate it :

v² + 4v - 21 = 0

v² - 3v + 7v - 21 = 0

Next, you have to collect like terms :

v(v - 3) + 7(v - 3) = 0

(v - 3)(v + 7) = 0

percentage - 25%

probability - 0.25

we know,

total amount of students in class = 20

total boys = 10

total girls = 10

no of girls who wear glasses = 10/2 = 5

probability of choosing a girl with glasses is =

number of girls wearing glasses/total number of students in the class = 5/20

thus, percentage of selecting a girl wearing glasses will be

= 5/20 × 100

= 5 × 5

25%

therefore,

probability will be 0.25

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