Cho tỉ lệ thức
giúp mik nha<style id="sweezy-cursors--styles" type="text/css">body a,
body button,
body [type='button'],
body input[type='reset'],
body input[type='submit'],
body [role="button"],
::-webkit-search-cancel-button,
::-webkit-search-decoration,
::-webkit-scrollbar-button,
::-webkit-file-upload-button,
body .sweezy-custom-cursor-hover {
cursor: url([removed]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") 6 3, pointer !important;<br />}<br /><br />html,<br />body,<br />body select,<br />body .sweezy-custom-cursor-default-hover {<br />cursor: url([removed]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") 1 1, auto !important;
}</style>
----- Nội dung dịch tự động từ ảnh -----
Câu 3. (1,5 điểm)
a +b?
a) Cho tỉ lệ thức
b
Chứng minh rằng:
d
(За + b)°
(3c +d)?
(với giả thiết các ti số đều có nghĩa).
=
c² +d?
b) Ba lớp 7A, 7B, 7C có số học sinh giỏi ti lệ với 6, 8, 9. Tính số học sinh giỏi của mỗi lớp biết lớp
7B có nhiều hơn lớp 7A là 8 học sinh giỏi.
body button,
body [type='button'],
body input[type='reset'],
body input[type='submit'],
body [role="button"],
::-webkit-search-cancel-button,
::-webkit-search-decoration,
::-webkit-scrollbar-button,
::-webkit-file-upload-button,
body .sweezy-custom-cursor-hover {
cursor: url([removed]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") 6 3, pointer !important;<br />}<br /><br />html,<br />body,<br />body select,<br />body .sweezy-custom-cursor-default-hover {<br />cursor: url([removed]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") 1 1, auto !important;
}</style>
----- Nội dung dịch tự động từ ảnh -----
Câu 3. (1,5 điểm)
a +b?
a) Cho tỉ lệ thức
b
Chứng minh rằng:
d
(За + b)°
(3c +d)?
(với giả thiết các ti số đều có nghĩa).
=
c² +d?
b) Ba lớp 7A, 7B, 7C có số học sinh giỏi ti lệ với 6, 8, 9. Tính số học sinh giỏi của mỗi lớp biết lớp
7B có nhiều hơn lớp 7A là 8 học sinh giỏi.