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Exponents and Powers — MATHS STD 7 — Question

Gujarat BoardEnglish MediumSTD 7MATHSExponents and Powers3 Marks
Question
Evaluate
(i) $(-1)^{19} \times(-1)^{26}$
(ii) $(-1)^{21}-(-1)^{22}$
✓

Answer

(i) We have, $(-1)^{19} \times(-1)^{26}$
$\because \quad(-1)^{19}=-1 \quad\left[\because(-1)^{\text {odd number }}=-1\right]$
and $\quad(-1)^{26}=1 \quad\left[\because(-1)^{\text {even number }}=1\right]$
So, $\quad(-1)^{19} \times(-1)^{26}=(-1) \times(1)=-1$
(ii) We have, $(-1)^{21}-(-1)^{22}$
$\because \quad(-1)^{21}=-1 \quad\left[\because(-1)^{\text {odd number }}=-1\right]$
and $\quad(-1)^{22}=1 \quad\left[\because(-1)^{\text {even number }}=1\right]$
So, $\quad(-1)^{21}-(-1)^{22}=(-1)-(1)=-2$

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