Question

If a + b = 9, ab = 4, find the value of a + b.
If a - b = 5, a + b2 = 49, find the value of ab.​

Answer 1

Answer:

Q1.If a + b = 9and ab = 4

Squaring both sides ,

$( {a}^{} + {b}^{} ) {}^{2} = {9}^{2}$

${a}^{2} + {b}^{2} + 2ab \: = 81$

${a}^{2} + {b}^{2} + 8 \: = 81$

${a}^{2} + {b}^{2} = 73$

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Answer 2

$\huge\underline{\underline{\bold{\red{A}\green{n}\pink{s}\orange{w}\blue{e}{r}}}}$

$a+b=9$

$\purple{Squaring\: both\: the\: sides}$

$⇝a^2+b^2+2ab\:=\:81$

$\orange{Substituting\: value\: of \:'ab' \:in \:equation:-}$

$⇝a^2+b^2+2 × 4\:=\:81$

$⇝a^2+b^2\:=\:73$

${\huge{\underline{\small{\bold{\red{hope\:help\:u :)}}}}}}$