Question

${(x + 4)}^{2} - {(x + 5)}^{2} = 9$
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Answer 1

(x+4)²‐(x+5)²=9

=>(x²+8x+16)‐(x²+10x+25)=9

=>x²+8x+16‐x²‐10x‐25=9

=>‐2x‐9=9

=>‐2x=9+9

=>x=‐18/2

=>x=‐9

FORMULA:–

(a+b)²=a²+2ab+b²