Question

How do you solve x²+2x−15≤0?

Answer 1

Answer:

Not sure but maybe

3x²-15≤0

Answer 2

Answer:

The solutions are

x=3

x=−5

Explanation:

x2+2x−15=0

We can Split the Middle Term of this expression to factorise it and thereby find solutions.

In this technique, if we have to factorise an expression like

ax2+bx+c , we need to think of 2 numbers such that

N^1⋅N^2=a⋅c=1⋅−15=−15

AND

N1+N2=b=2

After trying out a few numbers we get

N1=5

and N2=−3

5⋅−3=−15 , and 5+(−3)=2

x2+2x−15=x2+5x−3x−15

x(x+5)−3(x+5)=0

(x−3)(x+5)=0

Now we equate the factors to zero to find the solutions:

x−3=0,x=3x+5=0,

x=−5