Help me how to answer this please

Step-by-step explanation:

x^2 + 4x - 21 = 0

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

x = 3 or x = -7

x^2 - 14x = -24

x^2 - 14x + 24 = 0

(x - 12)(x - 2) = 0

x - 12 = 0 or x - 2 = 0

x = 12 or x = 2

2x^2 - 12 = 2x

x^2 - x - 6 = 0

(x - 3)(x + 2) = 0

x = 3 or x = -2

Topic: Factorisation

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d) 30 units^2

area of rectangle = l × b

we know,

length = 10 unit

breadth = 3 unit

applying the formula,

= l × b

= 10 × 3

= 30 unit^2

happy to

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details

step-by-step explanation: