Help please
Factorise
x²-x-56
its due in 4 minutes
2 answers:
Answer:
(x-8)(x+7)
Step-by-step explanation:
using quadratic formula we have
x= 
we have:
x^2-x-56=0
a= 1 b=-1 c=-56
so we have:
x=(-(-1)+-sqrt(1^1-4*(1)*(-56)))/(2*1)
x=1+-sqrt(1-4*(-56))/(2)
x=(1+-sqrt(225))/2
x=(1+-15)/2
so we have the roots:
x1=(1+15)/2 =8
x2=(1-15)/2=-7
so the answer is (x-8)(x+7)
x^2-x-56
Think of two numbers that will equal to -x and -56.
Use the 7 and 8 times table.
(x-8)(x+7)
Because - negative number * + positive number= - negative number
(x-8)(x+7)= 0
x-8= 0
Move -8 to the other side. Sign changes from -8 to +8.
x-8+8= 0+8
x= 8
x+7= 0
Move +7 to the other side. Sign changes from +7 to -7.
x+7-7= 0-7
x= -7
Answers:
x= 8 , x= -7
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