Question

X square plus X minus 12

Answer 1

Answer:

+3 and -4

Step-by-step explanation:

x²+x-12=0

we have to find a pair whose product is 12 and sum is +1..

the pairs and their sum and product are

pair|sum|product

1,12|13| 12(rejected as not satisfies the condition)

2,6|8|12(rejected as not satisfies the condition)

3,4|7|12(rejected as not satisfies the condition)

4,-3|1|-12(correct answer)

replace the correct pair with x

x²+4x-3x-12=0

now form pairs

(x²+4x)-(3x-12)=0

take out the common in both brackets

x(x+4) -3(x+4) =0

(x-3) (x+4) =0

equate both brackets

x-3=0 x+4=0

x=+3 x=-4

hence x=+3,-4