Nếu 2 số thực x, y thỏa <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-1"><span class="MJXp-mstyle" id="MJXp-Span-2"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-3">x</span><span class="MJXp-mo" id="MJXp-Span-4" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mn" id="MJXp-Span-5">3</span><span class="MJXp-mo" id="MJXp-Span-6" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-7">2</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-8">i</span><span class="MJXp-mo" id="MJXp-Span-9" style="margin-left: 0em; margin-right: 0em;">)</span><span class="MJXp-mo" id="MJXp-Span-10" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-11">y</span><span class="MJXp-mo" id="MJXp-Span-12" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mn" id="MJXp-Span-13">1</span><span class="MJXp-mo" id="MJXp-Span-14" style="margin-left: 0.267em; margin-right: 0.267em;">−</span><span class="MJXp-mn" id="MJXp-Span-15">4</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-16">i</span><span class="MJXp-mo" id="MJXp-Span-17" style="margin-left: 0em; margin-right: 0em;">)</span><span class="MJXp-mo" id="MJXp-Span-18" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-mn" id="MJXp-Span-19">1</span><span class="MJXp-mo" id="MJXp-Span-20" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-21">24</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-22">i</span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large x(3+2i)+y(1-4i)=1+24i</script> thì $\Large x-y

Nếu 2 số thực x, y thỏa x(3+2i)+y(14i)=1+24i thì $\Large x-y

4.2/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Câu hỏi:

Nếu 2 số thực x, y thỏa x(3+2i)+y(14i)=1+24i thì xy bằng

Đáp án án đúng là: D

Lời giải chi tiết:

x(3+2i)+y(14i)=1+24i(3x+y)+(2x4y)i=1+24i

{3x+y=12x4y=24 {x=2y=5 xy=7