Factorise and Solve x^2 + 10x + 15 = -6

To factorise an equation like this we must first make the equation equal to 0 therefore it becomes: x^2+10x+21.Now we have the equation in a way that we can work with it we can factorise.To do this we need to find 2 numbers that add to make 10 and times to make 21.3 and 7 both add to make 10 and times to make 21 therefore the factorised equation:x^2+10x+21 = (x+3)(x+7) = 0now we have the equation factorised we can solve it. to solve it we need to make x equal a number that will make each bracket = 0 as any number times 0 equals 0.if we sub in x = -3: (-3 +3) *(-3 +7) = 0, 0 * 4 = 0 therefore x =-3if we sub in x = -7: (-7 +3) ( -7 +7) =0, -4 * 0 = 0 therefore x = -7our answer to the question x=-3 and x=-7

Answered by Joseph V. Maths tutor

2674 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

The price of a book is £4. In a sale the price is reduced by 30%. Work out the sale price.


If f(x) = 5 – x and g(x) = 3x + 7, simplify f(2x) + g(x – 1)


The perimeter of a right-angled triangle is 60 cm. The lengths of its sides are in the ratio 3 : 4 : 5. Calculate the area of the triangle.


There are only red , blue and purple counters in a bag. The ratio of the number of red counters to the number of blue counters is 3 : 17. If a counter is taken randomly the probability that it is purple is 0.2 Work out the probability for it to be red.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences