Question

Solve each of the following equations, using the formula
class 10 ​

Answer 1

Answer:

1. x²-10x+21 = 0

a = 1, b = -10, c = 21

x = -b±√(b²-4ac)/2a

= 10±√(100-4(21)/2

= (10±√16)/2

= (10±4)/2

= (3±2)

2. x²+6x-10 = 0

a = 1, b = 6, c = -10

x = -b±√(b²-4ac)/2a

= -6±√(36+40)/2

= (-6±√76)/2

= -3±√19

3. x²+2x-6 = 0

a = 1, b = 2, c = -6

x = -b±√(b²-4ac)/2a

= -2±√(4+24)/2

= (-2±√28)/2

= -1±√7

4. 3x²+2x-1 = 0

a = 3, b = 2, c = -1

x = -b±√(b²-4ac)/2a

= -2±√(4+12)/6

= (-2±√16)/6

= (-2±4)/6

= (-1±2)/3

5. 2x²+7x+5 = 0

a = 2, b = 7, c = 5

x = -b±√(b²-4ac)/2a

= -7±√49-40)/4

= (-7±√9)/4

= (-7±3)/4

6. x²/15+5/3 = 2x/3

(÷15) x²+25 = 10x

x²-10x+25 = 0

(x+5)² = 0

x+5 = 0

x = -5