Solve the simultaneous equations
x + 7y = 15
x + 2y = 5

x=1, y=2

Step-by-step explanation:

x + 7y = 15

x + 2y = 5

Subtract the two equations

x + 7y = 15

-x - 2y =- 5

0x +5y = 10

Divide by 5

5y/5 = 10/5

y =2

Now find x

x+2y = 5

x +2(2) = 5

x +4 = 5

Subtract 4 from each side

x-4+4 = 5-4

x = 1

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form

total amount to be paid = $19.5

step-by-step explanation:

given ,

original price = $25.99

discount = 25%

discount amount = 25% of original price

discount amount = 25/100   * 25.99

discount amount = $6.49

hence , the total amount to be paid = original price - discount amount

                                                            = $25.99 - $6.49

                                                            =$19.5

total amount to be paid = $19.5